Configuring Basic Networks

Before Configuring Basic Networks

Connecting a Private IP Network to the Internet

Features Used

Configuration

Connecting a Public IP Network to the Internet

Features Used

Configuration

Connecting a Remote Office to a Corporate Office

Features Used

Cisco 800 Series Router Configuration

IP Routing Configuration

IPX Routing Configuration

Corporate Router Configuration

IP Routing Configuration

IPX Routing Configuration

Configuring Basic Networks

This chapter describes three networks that network administrators in small independent offices or that telecommuters can set up. You can familiarize yourself with the three networks, determining which one is best-suited for your situation.

The following are the three basic networks:

Private IP network to Internet
Public IP network to Internet
Remote office network to corporate office network using IP and IPX

The following sections contain information about preparing for the configurations and the steps to configure each of the three basic networks.

Before Configuring Basic Networks

Before configuring the three basic networks, you must do the following:

Step 1 Order an ISDN line from your telephone service provider. For complete information on ordering your ISDN line, see Appendix B, "Provisioning the ISDN Line."

Step 2 While ordering your ISDN line, gather the following information from your telephone service provider:

ISDN switch type.
Service profile identifiers (SPIDs). Only telephone service providers in North America assign SPIDs. SPIDs identify the ISDN B channels. The SPID format is generally an ISDN telephone number with additional numbers at the end; for example, 40855522220101. Depending on the switch that supports your ISDN line, your ISDN line could be assigned zero, one, or two SPIDs.
ISDN local directory numbers (LDNs), which are the local ISDN telephone numbers of your router. Examples are 4085552222 or 5553333.

Note The format of the LDN varies from region to region, depending on the telephone service provider. In some regions, you need to add the area code to the telephone number. Find out from your local telephone service provider whether or not you need to specify an area code for the LDN.

Step 3 If setting up an Internet connection, gather the following information from your Internet service provider (ISP):

Point-to-Point Protocol (PPP) client name that the ISP assigns as your login name.
PPP authentication type: Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP).
PPP password to access your ISP account.
IP address information: the IP address and subnet mask of the ISP ISDN interface. Also, if configuring a public IP network, you must gather the registered IP addresses and subnet masks to be used on your router LAN and WAN interfaces.
ISP telephone number.

Step 4 If setting up a connection to a corporate network, you and the network administrator of the corporate network must decide on or generate the following information for the WAN interfaces of the routers so you can both use this information:

PPP authentication type: CHAP or PAP.
PPP client name to access the router.
PPP password to access the router.
Telephone number assigned to the telephone interface of your router.

Step 5 If setting up either IP or IPX routing, obtain the following information:

IP address information: the addressing scheme for your IP network.
IPX address information: the addressing scheme for your IPX network.

Step 6 Decide which router configuration method to use:

Cisco 800 Fast Step application, a configuration tool for Windows 95, Windows NT, and Windows 98 that is included with the Cisco 800 series router. For more information, refer to the Cisco 800 Fast Step CD-ROM.
Router software command-line interface (CLI). This chapter describes the procedures for configuring your router using the CLI.

Note Cisco strongly recommends that inexperienced network administrators use the Cisco 800 Fast Step application to configure their routers.

Connecting a Private IP Network to the Internet

In the network example shown in Figure 3-1, the Cisco 800 series router connects a private IP network to an ISP.

Figure 3-1: Connecting Private IP Network to Internet

Features Used

This network uses the following features on the LAN:

IP routing
Dynamic Host Configuration Protocol (DHCP) server (optional)

When your router is acting as a DHCP server, workstations configured as DHCP clients are automatically assigned an IP address and subnet mask.

This network uses the following features on the WAN:

IP routing
PPP
Network Address Translation (NAT) overload
Internet Protocol Control Protocol (IPCP)
CHAP or PAP over PPP
Dial-on-demand routing (DDR)
Static routes

With NAT overload configured, the router uses one address for multiple hosts. With IPCP configured, your router automatically negotiates its IP address from the router it is attempting to connect to.

You can use either CHAP or PAP as the PPP authentication protocol. Cisco recommends using CHAP, because it is the more secure of the two protocols. For more information, see the "Selecting PPP Authentication Protocol" section in Appendix A, "Concepts."

In addition, the ISDN line is activated only when needed (DDR), using one route that has been manually configured (static route). DDR using static routes suits small networking environments that do not have complex routing topologies.

Configuration

Note Before you begin to configure your router, review "Before Configuring Basic Networks" earlier in this chapter.

To configure the features for this network example, perform the following steps on the PC from global configuration mode. For complete information on how to access global configuration mode, see "Entering Global Configuration Mode" in Chapter 2, "Basic Cisco IOS Skills." For more information on the commands used in this procedure, refer to the Cisco IOS documentation set.

Step 1 Specify a name for the router. For example, specify SanJose as the router name:

router(config)# hostname SanJose

Step 2 Specify an encrypted password with one to 25 uppercase or lowercase alphanumeric characters. Spaces are also valid password characters. Leading spaces are ignored; trailing spaces are recognized. For example, specify abra cadabra as the password:

SanJose(config)# enable secret abra cadabra

Step 3 Configure the router to recognize the zero subnet range as a valid range of addresses:

SanJose(config)# ip subnet-zero

Step 4 Disable the router from translating unfamiliar words entered during a console session into IP addresses:

SanJose(config)# no ip domain-lookup

Step 5 Optional. Configure your router as a DHCP server. Define the DHCP relay pool name. For example:

router(config)# ip dhcp pool DHCPpoolLAN_0

a. Set the DHCP pool of addresses. For example:

router(dhcp-config)# network 10.0.0.0 255.255.255.0

b. Set the IP addresses of the DNS servers. For example:

router(dhcp-config)# dns-server 192.168.1.100

c. Set the NetBIOS servers. For example:

router(dhcp-config)# netbios-name-server
10.1.1.2 10.1.1.3

d. Set the Ethernet 0 IP address as the default gateway. For example:

router(dhcp-config)# default-router 10.0.0.1

e. Exit to global configuration mode:

router(dhcp-config)# exit

Step 6 Configure the LAN interface by performing the following steps:

a. Specify parameters for the LAN interface:

SanJose(config)# interface ethernet0

b. Set the IP address and subnet mask for the LAN interface. For example:

SanJose(config-if)# ip address 10.0.0.1 255.0.0.0

c. Activate the LAN interface:

SanJose(config-if)# no shutdown

Step 7 Enable NAT on your LAN. The inside network address is not directly routed to the Internet, but is subject to translation to a routable address outside the LAN. For example:

SanJose(config-if)# ip nat inside

Step 8 Configure the WAN interface by performing the following steps:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Specify parameters for the WAN interface:

SanJose(config)# interface bri0

c. Enable PPP:

SanJose(config-if)# encapsulation ppp

d. Enable multilink PPP:

SanJose(config-if)# ppp multilink

e. Enable the translation of the inside network to a valid Internet address:

SanJose(config-if)# ip nat outside

f. Create a dialer rotary group, specifying a number between 0 and 255. Dialer rotary groups are useful in environments that require multiple calling destinations. For example:

SanJose(config-if)# dialer rotary-group 0

g. North America only. Associate the ISDN local directory numbers (LDNs) provided by your telephone service provider with the first and second SPIDs. You can specify the SPID number, or you can have it automatically detected by entering a 0.

: In the following example, the SPID number is represented by a 0, so that it will be automatically detected. The primary LDN is followed by the secondary LDN for each SPID.

SanJose(config-if)# isdn spid1 0 4085551111 4085552222
SanJose(config-if)# isdn spid2 0 4085553333 4085554444

Note Find out from your telephone service provider whether or not you need to specify an area code for the LDN.

h. North America only. If you had manually entered the SPID number, enable the BRI0 interface.

SanJose(config-if)# no shutdown

i. North America only. If you configured the SPID to be automatically detected, enable the automatic detection of ISDN SPID numbers and switch type:

SanJose(config-if)# isdn autodetect

j. Outside of North America only. Specify the ISDN switch type. To get a listing of supported switches, enter the isdn switch-type ? command.

: The following example specifies the NET3 switch type:

router(config-if)# isdn switch-type basic-net3

k. Disable the Cisco Discovery Protocol (CDP):

SanJose(config-if)# no cdp enable

Step 9 Follow these steps to specify characteristics of the dialer rotary group that were created in the previous step:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Create a dialer interface, specifying a number between 0 to 255 to represent your dialer rotary group. For example:

SanJose(config)# interface dialer 0
SanJose(config-if)#

c. Specify that the IP address for this interface is obtained by using IPCP:

SanJose(config-if)# ip address negotiated

d. Enable PPP as the encapsulation type:

SanJose(config-if)# encapsulation ppp

e. Enable DDR:

SanJose(config-if)# dialer in-band

f. Specify the amount of time in number of seconds that the line can be idle before it is disconnected:

SanJose(config-if)# dialer idle-timeout 300

g. Specify the telephone number of the interface to be called if you are calling a single site. For example:

SanJose(config-if)# dialer string 14085553333

h. Set the maximum number of packets to be held in the outgoing queue to 10. If an ISDN connection does not exist yet, the hold queue holds up to 10 packets before dropping them. For example:

SanJose(config-if)# dialer hold-queue 10

i. Define the load level that must be exceeded on the first ISDN B channel before the second B channel is brought up. The load-threshold variable represents a utilization percentage and is a number between 1 and 255, where 255 equals 100 percent. For example:

SanJose(config-if)# dialer load-threshold 10 outbound

Note Enter outbound to calculate the load using outbound data only, inbound to calculate the load using inbound data only, and either to set the maximum calculated load as the larger of the outbound and inbound loads.

j. Assign this interface to dialer access group 1:

SanJose(config-if)# dialer-group 1

k. Configure CHAP, then specify a CHAP host name and password. To configure PAP, skip this step and go to the next step.

: This command enables CHAP and specifies authentication on incoming calls only. Unidirectional authentication is used because non-Cisco routers that do not support bidirectional authentication are potentially in use at the ISP. In these cases, when the SanJose router calls the ISP, SanJose does not authenticate. However, the ISP authenticates SanJose before allowing the connection.

SanJose(config-if)# ppp authentication chap callin
router(config-if)# ppp chap hostname SanJose
router(config-if)# ppp chap password gocisco1

l. Configure PAP. To configure CHAP, skip this step and follow the previous step.

: The following command enables PAP and specifies authentication on incoming calls only. Unidirectional authentication is used because routers that do not support bidirectional authentication are potentially in use at the ISP. In these cases, when the SanJose router calls the ISP, SanJose does not authenticate. However, the ISP authenticates SanJose before allowing the connection.

SanJose(config-if)# ppp authentication pap callin

m. Enable remote PAP support for an interface. The username and password are sent in the PAP authentication request packet. The password must contain from 1 to 25 upper- and lowercase alphanumeric characters; it cannot contain spaces nor underscores.

SanJose(config-if)# ppp pap sent-username SanJose
password gocisco

n. Enable multilink PPP:

SanJose(config-if)# ppp multilink

Step 10 Follow these steps to configure how the IP routing protocol learns routes:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Set up all IP addresses to be treated as classless:

SanJose(config)# ip classless

c. Enable IP routing and set up a static route. Typically, the ISP does not provide IP addresses and subnet masks of their networks, but they do provide the IP address of the ISDN router interface to which your router is connected.

: The following example specifies that you need to use dialer 0 on your router to reach the ISP router. Dialer 0 had been previously configured using the interface dialer command.

SanJose(config)# ip routing
SanJose(config)# ip route 0.0.0.0 0.0.0.0 192.168.1.1
SanJOse(config)# ip route 192.168.1.1 255.255.255.255 dialer0

Step 11 Specify that dialer-list 1 permits dialing by the IP routing protocol:

SanJose(config)# dialer-list 1 protocol ip permit

Step 12 Perform this step only if ISDN calls at 64 kbps are not supported. Specify characteristics of the outgoing calls from an ISDN interface by using the following steps:

a. Define a class of shared configuration parameters for outgoing calls from an ISDN interface:

SanJose(config)# map-class dialer 56k

: The unique identifier that identifies the class is 56K.

b. Specify 56 kbps as the B channel speed:

SanJose(config-map-class)# dialer isdn speed 56

Step 13 If you have a Cisco 803 or Cisco 804 router that is connected to a telephone, fax machine, or modem, configure the telephone interfaces by performing the following steps:

a. Change to global configuration mode:

SanJose(config-map-class)# exit
SanJose(config)#

b. Specify the country where your router is located:

SanJose(config)# pots country us

: Enter the pots country ? command to get a list of supported countries and codes.

c. Create dial peers to determine how incoming calls are routed to the telephone ports. In the following example, the dial-peer tag is 1, the ISDN local directory number LDN is 5551111, the telephone port is 1, and call waiting is disabled:

SanJose(config)# dial-peer voice 1 pots
SanJose(config-dial-peer)# destination-pattern 5551111
SanJose(config-dial-peer)# port 1
SanJose(config-dial-peer)# no call-waiting
SanJose(config-dial-peer)# exit
SanJose(config)#

Note Enter a number from 1 to 6 for the dial-peer tag variable.

Find out from your telephone service provider whether or not you need to specify an area code for the LDN.

d. Specify parameters for the WAN interface:

SanJose(config)# interface bri0

e. Specify that incoming voice calls are forwarded to the devices connected to the telephone ports:

SanJose(config-if)# isdn incoming-voice modem

For more information, see Chapter 7, "Configuring Telephone Interfaces.

Step 14 Exit the interface configuration mode.

SanJose(config-if)# exit
SanJose#(config)#

Step 15 In global configuration mode, set global NAT commands. In the following example, all inside network addresses assigned to interface BRI0 are configured for translation, and the access list that contains the inside network addresses is defined.

SanJose(config)# ip nat inside source list 1 interface bri0
overload
SanJose(config)# access-list 1 permit 10.0.0.0 255.0.0.0

Step 16 Change to user mode and save your configuration:

SanJose(config)# exit
SanJose# copy running-config startup-config

Connecting a Public IP Network to the Internet

In the network example shown in Figure 3-2, the Cisco 800 series router connects a public IP network to an ISP. The ISP has assigned a range of registered (public) IP addresses for the LAN devices that require Internet access.

Figure 3-2: Connecting a Public IP Network to the Internet

Features Used

This network uses the following features on the LAN:

IP routing
DHCP server (optional)

When your router is acting as a DHCP server, workstations configured as DHCP clients are automatically assigned IP addresses and subnet masks.

This network uses the following features on the WAN:

IP routing
PPP
IPCP (optional)
CHAP or PAP over PPP
DDR
Static routes

If the ISP does not assign an IP address and subnet mask for your WAN interface, you can use IPCP to automatically negotiate its IP address from the router to which it is attempting to connect.

You can use either CHAP or PAP as the PPP authentication protocol. Cisco recommends using CHAP because it is the more secure of the two protocols. For more information, refer to the "Selecting PPP Authentication Protocol" section in Appendix A, "Concepts."

Configuration

Note Before you begin to configure your router, review "Before Configuring Basic Networks" earlier in this chapter.

To configure the features for this network example, perform the following steps on the PC from the global configuration mode. For complete information on how to access global configuration mode, refer to "Entering Global Configuration Mode" in Chapter 2, "Basic Cisco IOS Skills." For more information on the commands used in this procedure, see the Cisco IOS documentation set.

Step 1 Specify a name for the router. For example, specify SanJose as the router name:

router(config)# hostname SanJose

Step 2 Specify an encrypted password from one to 25 uppercase or lowercase alphanumeric characters. Spaces are valid password characters. Leading spaces are ignored but trailing spaces are recognized. For example:

SanJose(config)# enable secret abra cadabra

Step 3 Configure the router to recognize the zero subnet range as a valid range of addresses:

SanJose(config)# ip subnet-zero

Step 4 Disable the router from translating unfamiliar words entered during a console session into IP addresses:

SanJose(config)# no ip domain-lookup

Step 5 Optional. Configure your router as a DHCP server.

a. Define the DHCP relay pool name. For example:

router(config)# ip dhcp pool DHCPpoolLAN_0

b. Set the DHCP pool of addresses. For example:

router(dhcp-config)# network 10.0.0.0 255.255.255.0

c. Set the IP addresses of the DNS servers. For example:

router(dhcp-config)# dns-server 192.168.1.100

d. Set the NetBIOS servers. For example:

router(dhcp-config)# netbios-name-server
10.1.1.2 10.1.1.3

e. Set the Ethernet 0 IP address as the default gateway. For example:

router(dhcp-config)# default-router 10.1.1.1

f. Exit to global configuration mode.

router(dhcp-config)# exit

Step 6 Configure the LAN interface by performing the following steps:

a. Specify parameters for the LAN interface:

SanJose(config)# interface ethernet0

b. Set an IP address and subnet mask for the LAN interface. For example, set the IP address and subnet mask to 10.1.1.1 and 255.0.0.0, respectively:

SanJose(config-if)# ip address 10.1.1.1 255.0.0.0

Step 7 Configure the WAN interface by performing the following steps:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Specify parameters for the WAN interface:

SanJose(config)# interface bri0
SanJose(config-if)#

c. Enable PPP:

SanJose(config-if)# encapsulation ppp

d. Enable multilink PPP:

SanJose(config-if)# ppp multilink

e. Create a dialer rotary group, specifying a number between 0 and 255. Dialer rotary groups are useful in environments that require multiple calling destinations. For example:

SanJose(config-if)# dialer rotary-group 0

f. North America only. Associate the ISDN local directory numbers (LDNs) provided by your telephone service provider to the first and second SPIDs. You can specify the SPID number or you can have it automatically detected by entering a 0.

: In the following example, the SPID number is represented by a 0 so that it will be automatically detected. The primary LDN is followed by the secondary LDN for each SPID.

SanJose(config-if)# isdn spid1 0 4085551111 4085552222
SanJose(config-if)# isdn spid2 0 4085553333 4085554444

Note Find out from your telephone service provider whether or not you need to specify an area code for the LDN.

g. North America only. If you had manually entered the SPID number, enable the BRI0 interface.

SanJose(config-if)# no shutdown

h. North America only. If you had specified the automatic detection of SPID numbers, enable the automatic detection of ISDN SPID numbers and switch type:

SanJose(config-if)# isdn autodetect

i. Outside of North America only. Specify the ISDN switch type. To see a listing of supported switches, enter the isdn switch-type ? command.

: The following example specifies the NET3 switch:

SanJose(config-if)# isdn switch-type basic-net3

j. Disable Cisco Discovery Protocol (CDP).

SanJose(config-if)# no cdp enable

Step 8 Follow these steps to specify characteristics of the dialer rotary group that you created earlier:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Create a dialer rotary group leader and specify a number between 0 to 255 to represent your dialer rotary group. For example:

SanJose(config)# interface dialer 0

c. Set the IP address and subnet mask for the WAN interface provided by the ISP. For example:

SanJose(config-if)# ip address 192.168.1.2 255.255.255.0

d. Optional. If the ISP did not provide an IP address and subnet mask for the WAN interface, set up IPCP to obtain them from the router to which it is connecting:

SanJose(config-if)# ip address negotiated

e. Enable PPP:

SanJose(config-if)# encapsulation ppp

f. Enable DDR:

SanJose(config-if)# dialer in-band

g. Specify the amount of time (in seconds) that the line can be idle before it is disconnected. For example:

SanJose(config-if)# dialer idle-timeout 300

h. Specify a telephone number of the interface to be called if you are calling a single site. Enter the number 1 plus the telephone number if it is a long distance call. For example:

SanJose(config-if)# dialer string 14085553333

i. Set the number of packets to be held in the outgoing queue to 10. If an ISDN connection does not exist yet, the hold-queue holds up to 10 packets before dropping them. For example:

SanJose(config-if)# dialer hold-queue 10

j. Define the load level that must be exceeded on the first ISDN B channel before the second B channel is brought up. The load-threshold variable represents a utilization percentage and is a number between 1 and 255, where 255 equals 100 percent.

SanJose(config-if)# dialer load-threshold 10 outbound

k. Assign this interface to dialer access group 1:

SanJose(config-if)# dialer-group 1

l. Enable CHAP and configure the CHAP hostname and password. To configure PAP, skip this step, and go on to the next step.

: This command enables CHAP and specifies authentication on incoming calls only. Unidirectional authentication is used because non-Cisco routers that do not support bidirectional authentication are potentially in use at the ISP. In these cases, when SanJose calls the ISP, SanJose does not authenticate. However, the ISP authenticates SanJose before allowing the connection. For example:

SanJose(config-if)# ppp authentication chap callin
SanJose(config-if)# ppp chap hostname SanJose
SanJose(config-if)# ppp chap password gocisco1

m. Configure PAP. To configure CHAP, skip this step, and follow the previous step.

SanJose(config-if)# ppp authentication pap callin

: This command enables PAP and specifies authentication on incoming calls only. Unidirectional authentication is used because non-Cisco routers that do not support bidirectional authentication are potentially in use at the ISP. In these cases, when the SanJose router calls the ISP, the SanJose router does not authenticate the ISP router. However, the ISP authenticates the SanJose router before allowing the connection.

n. Enable remote PAP support for an interface. In the following example, the username and password (SanJose and gocisco1, respectively) are sent in the PAP authentication request packet. The password must contain from 1 to 25 uppercase and lowercase alphanumeric characters and cannot contain spaces or underscores.

SanJose(config-if)# ppp pap sent-username SanJose 
password gocisco1

o. Enable multilink PPP:

SanJose(config-if)# ppp multilink

Step 9 Follow these steps to configure how the IP routing protocol learns the routes:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Configure all IP addresses to be treated as classless:

SanJose(config)# ip classless

c. Set up static routes by entering the destination network, destination subnet mask, and the next hop address. In the following example, the IP address of the ISP router ISDN interface is 192.168.1.1. Typically, the ISPs do not provide IP addresses and subnet masks of their networks, but they do provide the IP addresses of the ISDN interfaces to which your router connects.

: The following example specifies 0.0.0.0 and 0.0.0.0 as the IP address and subnet mask of the ISP network, because you would not know these addresses.

SanJose(config)# ip route 0.0.0.0 0.0.0.0 dialer0

Step 10 Specify that dialer-list 1 permits dialing by the IP routing protocol:

SanJose(config)# dialer-list 1 protocol ip permit

Step 11 Perform this step only if ISDN calls at 64 kbps are not supported. Follow these steps to specify the characteristics of outgoing calls from an ISDN interface. The unique identifier for the class is 56k.

a. Define a class of shared configuration parameters for outgoing calls from an ISDN interface:

SanJose(config)# interface dialer 0
SanJose(config-if)# dialer string 5551212 class 56k
SanJose(config-if)# exit
SanJose(config)# map-class dialer 56k

b. Specify 56 kbps as the B channel speed:

SanJose(config-map-class)# dialer isdn speed 56

c. Change to global configuration mode:

SanJose(config-map-class)# exit
SanJose(config)#

Step 12 If you have a Cisco 803 or Cisco 804 router that is connected to a telephone, fax machine, or modem, configure the telephone interfaces by performing the following steps:

a. Specify the country where your router is located. For example:

SanJose(config)# pots country us

: This command determines the physical characteristics of the telephone interfaces. By specifying a country, you are configuring your telephone to use country-specific default settings for each of the physical characteristics. To get a list of supported countries and the code, enter the pots country ? command. For information on the physical characteristics and how to change the settings, see Chapter 7, "Configuring Telephone Interfaces."

b. Create dial peers to determine how incoming calls are routed to the telephone ports. In the following example, the dial-peer tag is 1, the ISDN local directory number (LDN) is 5551111, the telephone port is 1, and call waiting is disabled:

SanJose(config)# dial-peer voice 1 pots
SanJose(config-dial-peer)# destination-pattern 5551111
SanJose(config-dial-peer)# port 1
SanJose(config-dial-peer)# no call-waiting
SanJose(config-dial-peer)# exit

Note Enter a number from 1 to 6 for the dial-peer tag variable.

Find out from your telephone service provider whether or not you need to specify an area code for the LDN.

c. Specify parameters for the WAN interface:

SanJose(config)# interface bri0

d. Specify that incoming voice calls are forwarded to the devices connected to the telephone ports:

SanJose(config-if)# isdn incoming-voice modem

e. Change to user mode and save your configuration:

SanJose(config-if)# end
SanJOse# copy running-config startup-config

For more information, see Chapter 7, "Configuring Telephone Interfaces."

Connecting a Remote Office to a Corporate Office

In the network example shown in Figure 3-3, the Cisco 800 series router and another router, such as a Cisco 3600 router, connect the networks of a remote office and a corporate office by using a dial-on-demand ISDN line. The routes between the two routers are static IP and IPX routes that you configure.

Figure 3-3: Remote Office to Corporate Office

Features Used

This network uses the following features on the LAN:

IP routing (Cisco recommends for management purposes, such as Telnet)
IPX routing
DHCP server (optional)

When your router is acting as a DHCP server, workstations configured as DHCP clients are automatically assigned an IP address and subnet mask.

This network uses the following features on the WAN:

IP routing
IPX routing
PPP
IPCP
CHAP or PAP over PPP
DDR
Static routes

With IPCP configured, your router automatically negotiates its IP address from the router it is attempting to connect to.

Because DDR is configured, the ISDN line is activated only when needed using one route that has been manually configured (static route). Because a static route is configured, the routers do not need to exchange routing updates. As a result, the ISDN line is activated only when traffic demands.

Cisco 800 Series Router Configuration

Note Before you begin to configure your router, review "Before Configuring Basic Networks" earlier in this chapter.

To configure the features for this network example, perform the following steps on the PC from the global configuration prompt. For complete information on how to access global configuration mode, refer to the "Entering Global Configuration Mode" section in Chapter 2, "Basic Cisco IOS Skills." For more information on the commands used in this procedure, see the Cisco IOS documentation set.

Step 1 Specify a name for the router. For example:

router(config)# hostname SanJose

Step 2 Specify an encrypted password. For example:

SanJose(config)# enable secret password

Step 3 Specify the username of any client that will potentially dial into your router and the password that your router and the client will share. Specify the username and password of the central office router (the central office network administrator should provide this information). For example:

SanJose(config)# username LosAngeles password gocisco1

Step 4 Optional. Configure your router as a DHCP server:

a. Define the DHCP relay pool name. For example:

router(config)# ip dhcp pool DHCPpoolLAN_0

b. Set the DHCP pool of addresses. For example:

router(dhcp-config)# network 10.1.0.0 255.255.0.0

c. Set the IP addresses of the DNS servers. For example:

router(dhcp-config)# dns-server 192.168.1.0 255.255.255.0

d. Set the NetBIOS servers. For example:

router(dhcp-config)# netbios-name-server
10.1.0.2 10.1.0.3

e. Set the Ethernet 0 IP address as the default gateway. For example:

router(dhcp-config)# default-router 10.1.0.1

Step 5 Configure the WAN interface by performing the following steps:

a. Change to global configuration mode:

SanJose(dhcp-config)# exit
SanJose(config)#

b. Specify parameters for the WAN interface:

SanJose(config)# interface bri0
SanJose(config-if)#

c. Enable PPP:

SanJose(config-if)# encapsulation ppp

d. Enable multilink PPP:

SanJose(config-if)# ppp multilink

e. Create a dialer rotary group, specifying a number between 0 and 255. Dialer rotary groups are useful in environments that require multiple calling destinations. For example:

SanJose(config-if)# dialer rotary-group 0

: In the following example, the SPID number is represented by a 0 so that it would be automatically detected. The primary LDN is followed by the secondary LDN for each SPID.

SanJose(config-if)# isdn spid1 0 4085551111 4085552222
SanJose(config-if)# isdn spid2 0 4085553333 4085554444

Note Find out from your telephone service provider whether or not you need to specify an area code for the LDN.

g. North America only. If you had entered the SPID number, enable the BRI0 interface.

SanJose(config-if)# no shutdown

h. North America only. If you configured the SPID to be automatically detected, enable the automatic detection of ISDN SPID numbers and switch type:

SanJose(config-if)# isdn autodetect

i. Outside of North America only. Specify the ISDN switch type. To see a listing of supported switches, enter the isdn switch-type ? command.

: The following example specifies the NET3 switch:

SanJose(config-if)# isdn switch-type basic-net3

j. Disable CDP.

SanJose(config-if)# no cdp enable

Step 6 Specify characteristics of the dialer rotary group created earlier by performing the following steps:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Create a virtual interface by specifying a number between 0 to 255 to represent your dialer rotary group.

SanJose(config)# interface dialer 0

c. Enable PPP:

SanJose(config-if)# encapsulation ppp

d. Enable DDR:

SanJose(config-if)# dialer in-band

e. Specify the amount of time (in seconds) that the line can be idle before it is disconnected. For example:

SanJose(config-if)# dialer idle-timeout 300

f. Set the number of packets to be held in the outgoing queue to 10. If an ISDN connection does not exist yet, the hold-queue holds up to 10 packets before dropping them. For example:

SanJose(config-if)# dialer hold-queue 10

g. Define the load level that must be exceeded on the first ISDN B channel before the second B channel is brought up. The load-threshold variable represents a utilization percentage and is a number between 1 and 255, where 255 equals 100 percent.

SanJose(config-if)# dialer load-threshold 150 outbound

h. Assign this interface to dialer access group 1:

SanJose(config-if)# dialer-group 1

i. Configure CHAP. To configure PAP, skip this step, and go on to the next step. This command enables CHAP and specifies authentication on incoming and outgoing calls.

SanJose(config-if)# ppp authentication chap

j. Configure PAP. To configure CHAP, skip this step, and go to the previous step. This command enables PAP and specifies authentication on incoming and outgoing calls.

SanJose(config-if)# ppp authentication pap

k. Enable multilink PPP, then return to global configuration mode:

SanJose(config-if)# ppp multilink
SanJose(config-if)# exit

Step 7 Perform this step only if ISDN calls at 64 kbps are not supported on your line. Specify the characteristics of outgoing calls from an ISDN interface by performing the following steps:

a. Define a class of shared configuration parameters for outgoing calls from an ISDN interface:

SanJose(config)# interface dialer 0
SanJose(config-if)# dialer string 5551212 class 56k
SanJose(config-if)# exit
SanJose(config)# map-class dialer 56k

b. Specify 56 kbps as the B channel speed:

SanJose(config-map-class)# dialer isdn speed 56

c. Change to global configuration mode:

SanJose(config-map-class)# exit
SanJose(config)#

Step 8 If you have a Cisco 803 or Cisco 804 router that is connected to a telephone, fax machine, or modem, configure the telephone interface by performing the following steps:

a. Specify the country where your router is located. For example:

SanJose(config)# pots country us

: This command determines the physical characteristics of the telephone interfaces. By specifying a country, you are configuring your telephone to use country-specific default settings for each of the physical characteristics. To get a list of supported countries and the code, enter the pots country ? command. For information on the physical characteristics and how to change the settings, refer to Chapter 7, "Configuring Telephone Interfaces."

SanJose(config)# dial-peer voice 1 pots
SanJose(config-dial-peer)# destination-pattern 5551111
SanJose(config-dial-peer)# port 1
SanJose(config-dial-peer)# no call-waiting
SanJose(config-dial-peer)# exit
SanJose(config)#

Note Find out from your telephone service provider whether or not you need to specify an area code for the LDN.

c. Specify parameters for the WAN interface:

SanJose(config)# interface bri0

d. Specify that incoming voice calls are forwarded to the devices connected to the telephone ports:

SanJose(config-if)# isdn incoming-voice modem

For more information, see Chapter 7, "Configuring Telephone Interfaces."

IP Routing Configuration

To configure IP routing, perform the following steps on your PC:

Step 1 Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

Step 2 Configure the router to recognize the zero subnet range as a valid range of addresses:

SanJose(config)# ip subnet-zero

Step 3 Disable the router from translating unfamiliar words entered during a console session into IP addresses:

SanJose(config)# no ip domain-lookup

Step 4 Configure the LAN interface by performing the following steps:

a. Specify parameters for the LAN interface:

SanJose(config)# interface ethernet0

b. Set an IP address and subnet mask for the LAN interface. For example:

SanJose(config)# ip address 10.1.0.1 255.255.0.0

Step 5 Follow these steps to specify characteristics of the dialer rotary group that were created earlier:

a. Specify parameters for the dialer rotary group:

SanJose(config)# interface bri0

b. Specify the IP address under the dialer group 1:

SanJose(config-if)# dialer-group 1
SanJose(config-if)# ip address 10.3.1.1 255.255.0.0

c. Specify that there are no IP addresses assigned for this interface:

SanJose(config-if)# no ip address
SanJose(config-if)#

d. To configure the WAN interface to call a site or to receive calls from a site, create a dialer map. In the following example, the same command is entered twice, once for each dial string provided for the two B channels. The next hop address is 10.3.1.2 and the host name is LosAngeles in both entries.

SanJose(config-if)# dialer map ip 10.3.1.2 
name LosAngeles speed 56 14085553333
 
SanJose(config-if)# dialer map ip 10.3.1.2 
name LosAngeles speed 56 14085554444

Step 6 Follow these steps to configure how the IP routing protocol learns the routes:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Configure all IP addresses to be treated as IP classless addresses:

SanJose(config)# ip classless

c. Set up static routes. In the following example, the LosAngeles local network is 10.2.0.0, the subnet mask is 255.255.0.0, and the router ISDN interface is 10.2.0.1:

SanJose(config)# ip route 10.2.0.0 255.255.0.0 10.2.1.2

Note You must configure the route to the LosAngeles network as well as the route to the LosAngeles router ISDN interface. The route to the LosAngeles router is through the dialer 0 port of the SanJose router.

Step 7 Specify that dialer-list 1 permits dialing by the IP routing protocol:

SanJose(config)# dialer-list 1 protocol ip permit

IPX Routing Configuration

To configure IPX routing, perform the following steps on your PC.

Step 1 Enable IPX routing:

SanJose(config)# ipx routing

Note The router uses the Media Access Control (MAC) address of the Ethernet port as the node address. Cisco 803 and Cisco 804 routers use the MAC address of Ethernet port 0.

Step 2 Configure the LAN interface by performing the following steps:

a. Specify parameters for the LAN interface:

SanJose(config)# interface ethernet0

b. Enable IPX routing on a particular interface and select the primary and secondary types of encapsulation (framing). In this network example, the network numbers are 100 and 101 in Figure 3-3. The keyword sap specifies the Novell Ethernet 802.2 as the primary encapsulation, and novell-ether specifies the Novell Ethernet 802.3 as the secondary encapsulation.

SanJose(config)#ipx network 100 encapsulation sap
SanJose(config)#ipx network 101 
encapsulation novell-ether secondary

Step 3 Use the following steps to specify characteristics of the dialer rotary group created in the "Cisco 800 Series Router Configuration" section:

a. Enable IPX routing under interface BRI 0 for the WAN interface. In the following example, the network number is AAAA:

SanJose(config)# interface bri0
SanJose(config-if)# ipx network AAAA

b. Disable IPX fast switching:

SanJose(config-if)# no ipx route-cache

c. Specify parameters for the WAN interface:

SanJose(config-if)# interface dialer 0

d. Set up the software to respond to watchdog packets of a server on behalf of a remote client:

SanJose(config-if)# ipx watchdog-spoof

e. Create a dialer map to configure the WAN interface to call a site or to receive calls from a site. In the following example, this command is entered twice, once for each B channel. For both commands, the next hop address is AAAA.0000.0cbb.2222 and the host name is LosAngeles. The dial strings are 15553333 and 15554444.

SanJose(config-if)# dialer map ipx AAAA.0000.0cbb.2222
name LosAngeles speed 56 15553333
 
SanJose(config-if)# dialer map ip 10.3.1.2 
name LosAngeles speed 56 15554444

Step 4 Follow these steps to configure how the IPX routing protocol learns routes:

a. Change to global configuration mode:

SanJose(config-if)# exit
SanJose(config)#

b. Set up static routes. The following example specifies 200 for the network where you want to establish a static route and AAAA.0000.0cbb.2222 for the network (AAAA) and node (0000.0cbb.2222) where packets destined for network 200 should be forwarded.

SanJose(config)# ipx route 200 AAAA.0000.0cbb.2222

c. Specify static Service Advertising Protocol (SAP) entries. The following example specifies 4 as the SAP service-type number, LosAngelesFS as the name, 2000.0000.0000.0001 as the network number and node address of the server, 451 as the socket number for this service, and 2 as the number of hops to the server.

SanJose(config)# ipx sap 4 LosAngelesFS 2000.0000.0000.0001
451 2

Step 5 Specify that dialer-list 1 permits dialing by the IPX routing protocol:

SanJose(config)# dialer-list 1 protocol ipx permit

Step 6 End your router session:

SanJose(config)# end

Corporate Router Configuration

To configure the features for this sample network, perform the following steps on your PC from global configuration mode. This section assumes that the router connected to the Cisco 800 series router is a Cisco router that supports Cisco IOS software, for example, a Cisco 3600 router. For more information, refer to the documentation that accompanied your other Cisco router.

Step 1 Specify a name for the router, for example, LosAngeles:

router# hostname LosAngeles

Step 2 Specify an encrypted password, for example, abra cadabra:

LosAngeles# enable secret abra cadabra

Step 3 Specify the username of any client that will potentially dial in to your router and the password that your router and the client will share. The following example specifies SanJose and gocisco1 as the username and password:

LosAngeles# username SanJose password gocisco1

Step 4 Change to global configuration, then to interface configuration mode. Specify the ISDN switch type. To get a listing of supported switches, enter the isdn switch-type ? command.

LosAngeles# configure terminal
LosAngeles(config)# interface bri0
LosAngeles(config-if)# isdn switch-type basic-net3

To specify a National ISDN-1 (NI1) switch, enter the following:

LosAngeles(config)# isdn switch-type basic-ni1

Step 5 Optional. Configure your router as a DHCP server:

a. Define the DHCP relay pool name. For example:

LosAngeles(config)# ip dhcp pool DHCPpoolLAN_0

b. Set the DHCP pool of addresses. For example:

LosAngeles(dhcp-config)# network 10.2.0.0 255.255.0.0

c. Set the IP addresses of the DNS servers. For example:

LosAngeles(dhcp-config)# dns-server 172.29.20.41 172.29.20.51

d. Set the NetBIOS servers. For example:

LosAngeles(dhcp-config)# netbios-name-server
10.2.0.2 10.2.0.3

e. Set the Ethernet 0 IP address as the default gateway. For example:

LosAngeles(dhcp-config)# default-router 10.2.0.1

f. Exit to global configuration mode.

LosAngeles(dhcp-config)# exit

Step 6 Configure the WAN interface by performing the following steps:

a. Specify parameters for the WAN interface:

LosAngeles(config)# interface bri0

b. Enable PPP:

LosAngeles(config-if)# encapsulation ppp

c. Enable multilink PPP:

LosAngeles(config-if)# ppp multilink

d. Create a dialer rotary group, specifying a number between 0 and 255. Dialer rotary groups are useful in environments that require multiple calling destinations. For example:

LosAngeles(config-if)# dialer rotary-group 0

e. North America only. Specify the SPID numbers assigned to your B channels, using the isdn spid1 command for the B1 channel and the isdn spid2 command for the B2 channel. For example:

LosAngeles(config-if)# isdn spid1 0155533330101
LosAngeles(config-if)# isdn spid2 0155544440101

f. Disable CDP.

LosAngeles(config-if)# no cdp enable

Step 7 Specify characteristics of the dialer rotary group created earlier by following these steps:

a. Change to global configuration mode:

LosAngeles(config-if)# exit
LosAngeles(config)#

b. Create a dialer rotary group leader. Specify a number between 0 to 255 to represent your dialer rotary group.

LosAngeles(config)#interface dialer 0

: .

c. Enable PPP:

LosAngeles(config-if)# encapsulation ppp

d. Enable DDR:

LosAngeles(config-if)# dialer in-band

e. Specify the amount of time (in seconds) that the line can be idle before it is disconnected. For example:

LosAngeles(config-if)# dialer idle-timeout 300

: Set the number of packets to be held in the outgoing queue to 10. In the following example, if an ISDN connection does not exist yet, the hold queue holds up to 10 packets before dropping them.

LosAngeles(config-if)# dialer hold-queue 10

f. Define the load level that must be exceeded on the first ISDN B channel before the second B channel is brought up.The load variable represents a utilization percentage and is a number between 1 and 255, where 255 is 100 percent.

LosAngeles(config-if)# dialer load-threshold 10 outbound

g. Assign this interface to dialer access group 1. The dialer access group is defined later in this procedure.

LosAngeles(config-if)# dialer-group 1

h. Configure CHAP. To configure PAP, skip this step, and go on to the next step. This command enables CHAP and specifies authentication on incoming and outgoing calls.

LosAngeles(config-if)# ppp authentication chap

: Configure PAP. To configure CHAP, skip this step, and go to the previous step. This command enables PAP and specifies authentication on incoming and outgoing calls.

LosAngeles(config-if)# ppp authentication pap

i. Enable multilink PPP:

LosAngeles(config-if)# ppp multilink

IP Routing Configuration

To configure IP routing, perform the following steps on the PC connected to the other router.

Step 1 Change to global configuration mode:

LosAngeles(config-if)# exit
LosAngeles(config)#

Step 2 Specify the subnet 0.0.0.0 for your IP network:

LosAngeles(config)# ip subnet-zero

Step 3 Disable the IP DNS-based host name-to-address translation:

LosAngeles(config)# no ip domain-lookup

Step 4 Configure the LAN interface by performing the following steps:

a. Specify parameters for the LAN interface:

LosAngeles(config)# interface ethernet0

b. Set an IP address and subnet mask for the LAN interface. For example:

LosAngeles(config)# ip address 10.2.0.1 255.255.0.0

Step 5 Follow these steps to specify characteristics of the dialer rotary group that were created earlier:

a. Change to global configuration mode:

LosAngeles(config-if)# exit
LosAngeles(config)#

b. Specify parameters for the dialer rotary group:

LosAngeles(config)# interface dialer 1

c. Set an IP address and subnet mask for this interface:

LosAngeles(config-if)# ip address 10.3.1.2 255.255.0.0

d. To configure the WAN interface to call a site or to receive calls from a site, create a dialer map in global configuration mode.

: In this example, this command is entered twice, once for each B channel. The next hop address is 10.3.1.1, the host name is SanJose, and the dial strings are 408555111100 and 408555222200:

LosAngeles(config-if)# exit
LosAngeles(config)# dialer map ip 10.3.1.1 name SanJose 
speed 56 408555111100
LosAngeles(config)# dialer map ip 10.3.1.1 name SanJose 
speed 56 408555222200

Step 6 Follow these steps to configure how the IP routing protocol learns routes:

a. Change to global configuration mode:

LosAngeles(config-if)# exit
LosAngeles(config)#

b. Set up all IP addresses to be treated as classless:

LosAngeles(config)# ip classless

c. Set up static routes. In the following example, the destination (SanJose) network is 10.1.0.0, the subnet mask is 255.255.0.0, and the SanJose router ISDN interface is 10.3.1.1.

LosAngeles(config)# ip route 10.1.0.0 255.255.0.0 10.3.1.1

Note You must configure the route to the SanJose network as well as the route to the SanJose router ISDN interface. The route to the SanJose router is through the dialer 0 port of the LosAngeles router.

Step 7 Specify that dialer list 1 permits dialing by the IP routing protocol:

LosAngeles(config)# dialer-list 1 protocol ip permit

IPX Routing Configuration

To configure IPX routing, perform the following steps on the PC connected to the other router.

Step 1 Enable IPX routing:

LosAngeles(config)# ipx routing

The router uses the Media Access Control (MAC) address of the first Ethernet port as the node address.

Step 2 Configure the LAN interface by performing the following steps:

a. Specify parameters for the LAN interface:

LosAngeles(config)# interface ethernet0

b. Enable IPX routing on a particular interface. In the following example, the network number is 200.

LosAngeles(config-if)# ipx network 200

c. Change to global configuration mode:

LosAngeles(config-if)# exit
LosAngeles(config)#

Step 3 Follow these steps to specify characteristics of the dialer rotary group that were created earlier:

a. Enable IPX routing on the WAN interface. In the following example, the network number is AAAA.

LosAngeles(config)# interface bri0
LosAngeles(config-if)# ipx network AAAA

b. Disable IPX fast switching:

LosAngeles(config-if)# no ipx route-cache

c. Specify parameters for the WAN interface:

LosAngeles(config-if)# interface dialer 0

d. Set up the software to respond to watchdog packets of a server on behalf of a remote client:

LosAngeles(config-if)# ipx watchdog-spoof

e. Create a dialer map to configure the WAN interface to call a site or to receive calls from a site. In the following example, the same command is entered twice, once for each B channel. For both commands, the next hop address is AAAA.0000.0caa.1111 and the host name is SanJose. The dial strings are 408555111100 and 408555222200.

LosAngeles(config-if)# dialer map ipx AAAA.0000.0caa.1111
name SanJose speed 56 408555111100
 
LosAngeles(config-if)# dialer map ipx AAAA.0000.0caa.1111
name SanJose speed 56 408555222200

Step 4 Follow these steps to configure how the IPX routing protocol learns routes:

a. Change to global configuration mode:

LosAngeles(config-if)# exit
LosAngeles(config)#

b. Set up static routes. In the following example, 100 is the network to which you want to establish a static route and AAAA.0000.0caa.1111 for the network (AAAA) and node (0000.0caa.1111) to which packets destined for network 100 should be forwarded.

LosAngeles(config)# ipx route 100 AAAA.0000.0caa.1111

c. Specify static SAP entries by adding a static SAP entry for the SanJose file server. The following example specifies 4 as the SAP service-type number, SanJoseFS as the name, 1000.0000.0000.0001 as the network number and node address of the server, 451 as the socket number for this service, and 2 as the number of hops to the server.

LosAngeles(config)# ipx sap 4 SanJoseFS 1000.0000.0000.0001 
451 2

Step 5 Specify that dialer-list 1, which was defined earlier, permits dialing by the IPX routing protocol:

LosAngeles(config)# dialer-list 1 protocol ipx permit

Step 6 End your router session:

SanJose(config)# end
SanJose# disable
SanJose> logout

Table of Contents

Configuring Basic Networks