Network Registrar Features

Cisco Network Registrar (CNR) is a full-featured, scalable DNS and DHCP system for large IP networks. It provides the key benefits of stabilizing the IP infrastructure, automating networking services including client configuration and provisioning cable modems, and providing the foundation of user-based policies for CiscoAssure Policy Networking.

With unique features that enable integration with other network infrastructure software and business applications, Cisco Network Registrar enables enterprise and service provider users to better manage their networks.

Target Users

Cisco Network Registrar is designed for managers of large business enterprises and for Internet Service Providers.

Large Enterprises---Can benefit from the automation of the tasks of assigning IP addresses and configuring the TCP/IP software in individual network devices. Forward-looking enterprise users can take advantage of the Cisco Network Registrar LDAP directory interface, Class of Service, and other features that enable integration with new or existing network management applications such as, user registration.
Cable Internet Service Providers---Can benefit from services and tools that provide reliable and manageable Dynamic Host Configuration Protocol (DHCP) and Domain Name (DNS) services that meet the Data Over Cable Service Interface Specification (DOCSIS). Cisco Network Registrar provides policy-based, robust, and scalable DNS and DHCP services, that form the basis for a complete cable-modem provisioning system.
Internet Service Providers---Can benefit from these features that drive down the cost of operating their networks. Because many service providers are already committed to the use of LDAP directories as the enabler for integrating the components of their network infrastructure, Cisco Network Registrar is an excellent choice.

Cisco Network Registrar Features

Cisco Network Registrar includes a wide range of unique and standard features that provide users with numerous benefits over competing products and public domain software. The most critical benefits are stabilizing the IP infrastructure, automating network services, and preparing for policy networking.

Table 1-1 describes Cisco Network Registrar features and benefits. The table is divided into DNS server, DHCP server, and architecture and user interface sections.

Table 1-1: Cisco Network Registrar Features and Benefits

Feature Description Benefit

DNS Server

Classless in-addr.arpa zones

Supports use of the best practices described in RFC 2317. (Note: Network Registrar does not automatically generate the large number of alias records suggested in the RFC)

Helps support a wide variety of network topologies and DNS zone structures.

DNS subzone hiding

The DNS server can hide the subzone hierarchy for all zones delegated from a server. When enabled, the DNS server will not transfer NS and SOA records for a subzone during a zone transfer. Standard DNS queries continue to work.

Hides sensitive information about the topology of the network and devices on the network.

Dynamic DNS Updates

Allows DNS clients and DHCP servers to dynamically update DNS with new IP addresses and DNS name mappings. (RFC 2136) Network Registrar is the only DNS/DHCP product that implements dynamic DNS updates using this standard protocol.

Automatically registers clients in DNS and eliminates DNS management overhead.

Import zone files

Allows import of DNS information in the BIND zone file format; either individual files or all files specified in a named.boot file.

Speeds migration from BIND to Network Registrar.

Incremental zone transfers

Transfers only the incremental changes in a DNS zone during a zone transfer. Network Registrar is the only DNS server to support Incremental Zone Transfers. (RFC 1995)

Dramatically reduces time and bandwidth required to propagate DNS updates throughout a network. Particularly valuable if updates must traverse expensive WAN links

Internal root

Allows configuration of a DNS server as an internal root server.

Supports IP networks that are not connected to the Internet.

Interoperable with BIND

Interoperates with BIND and other RFC-compliant DNS servers. Network Registrar can be primary to a BIND secondary and vice-versa.

Supports mixed environments and a phased migration from BIND.

Notify

Primary DNS server notifies secondary DNS servers of changes to zone information. (RFC 1996)

Speeds up the propagation of dynamic DNS information.

Persistent cache

DNS cache data is stored in indexed disk files. Controls the amount of physical memory used by the DNS server. Preserves DNS cache data across system or server restarts.

Improves performance and reduces amount of memory used by the DNS server. Prevents thrashing which is caused when the DNS server consumes all physical memory.

Preconfigured root server

Preconfigured with the names and addresses of the Internet root name servers. Can be updated or overridden if needed.

Speeds and simplifies installation and configuration.

Resolution exception (Selective Forwarding)

Selectively forwards DNS queries for specified domains to internal DNS servers rather than recursively querying the root name servers on the Internet and external DNS servers.

Allows DNS to work among subsidiaries (intranets) or trading partners (extranets) without using the Internet, and thus improving network privacy.

Round-robin

If one name owns multiple A records (address records), the order of the records is rotated in successive queries for that name.

Provides a rudimentary form of load balancing. (Note: Cisco Local Directors and Distributed Director are superior solutions for load balancing)

SRV records

Supports SRV records, including dynamic DNS update of SRV records. ("Experimental" RFC 2052)

Windows 2000 compatibility. Microsoft has identified this feature as required for DNS servers in a Windows 2000/Active Directory environment.

Subnet sorting

When the DNS resolver (client), DNS server, and target are all on the same subnet, and the target has multiple addresses (A records), the server will list, in the reply, the address on the common subnet first.

CDDM compatibility feature

DHCP Server

BOOTP and Dynamic BOOTP

Supports BOOTP, which assigns addresses and configuration information to clients based on the client's MAC address and Dynamic BOOTP, which dynamically assigns IP addresses and shares an IP address pool with the DHCP server.

Supports older BOOTP clients, including many network printers

Class of service (client and client-class)

Supports customization of IP address, DHCP options, and fully-qualified domain name based on client's M AC address. Similar clients can be grouped into classes, and customization applied to the class. Can deny addresses to clients or classes

Supports the integration of CNR with a variety of network infrastructure applications

Supports integration with CiscoAssure Policy Networking

Supports DOCSIS cable modems

DHCP Custom Options

Allows configuration of new DHCP options

Flexibility in supporting options required by custom DHCP clients, or options standardized between revisions of Cisco Network Registrar

DHCP Option Validity

Compliance with RFC 2132.

Ensures standard option definition.

DHCP relay agent option

Supports the DHCP relay agent option, as specified in draft-ietf-dhc-agent-options.

Supports DOCSIS modems

DOCSIS modem support

Includes features needed by DOCSIS modems. These include:

Support for relay agent option

Class of service (allows DHCP server to distinguish between a DOCSIS modem and a user device, and configure each correctly)

Support for non-requested options (return specified options to modems even if they don't request them)

Supports data-over-cable service providers

Dynamic DNS updates

DHCP server updates the DNS server with two records each in the forward and reverse zones. The forward zone receives an A record (Name and IP address) and a TXT record with the client ID (client ID = MAC address for Microsoft clients). The reverse zone receives a PTR record (IP address and name) and a TXT record with the client ID. Uses RFC 2136 Dynamic DNS Update Protocol

Automatically registers DHCP clients in DNS and eliminates DNS management overhead.

Extension points

Allows custom handling of individual DHCP packets as the DHCP server processes them. Extensions can be written in TCL scripting language or C, C++ compiled languages.

Supports additional levels of customization of individual DHCP clients.

Failover

Allows redundant DHCP servers to provide leases in the event of server failure

Provides a high-availability DHCP service. Clients requesting leases need not know or care which server is responding to their requests for leases.

Flexible name options

Supports a variety of techniques for selecting DNS names:

As requested by client (end-user controlled)

As specified in directory entry for client

Synthesized from MAC address

Flexibility

LDAP directory support

Can read client information from an LDAP directory; can update the directory with lease data.

Supports DEN

Supports integration with other network infrastructure applications

Multiple network interfaces

Supports DHCP server systems with multiple network interfaces.

Reduces network traffic on multiple network segments.

NetWare Options

Supports the NetWare options in RFCs 2241 and 2242.

Supports customers with NetWare

PING before offering lease

Before the DHCP server offers an IP address to a DHCP client, the DHCP server pings the network.

Prevents duplicate IP address assignments.

Secondary Subnets

Allows administrators to create DHCP address pools (scopes) that have addresses from multiple logical subnets that are on the same physical network.

Supports numerous network configurations and allows networks to be easily renumbered.

Supports all DHCP allocation methods

Supports all three allocation methods specified in RFC 2131:

Automatic (permanent lease)

Dynamic (temporary lease)

Manual (reserved address)

Flexibility and standards support

Utilization alerts

Generates e-mail notices if the percentage or number of available addresses on one or more subnets falls below a configurable threshold

Alerts administrators of impending problems, allowing timely corrective action

Variable-length subnet masks

Address pools for different IP subnets can have different subnet masks.

Allows for flexible addressing schemes including OSPF configurations.

Registrar Architecture and User Interfaces

Command line interface

All aspects of Network Registrar can be configured with the CLI.

Repetitive tasks can be automated with scripts. Configuration can be integrated with other network infrastructure applications.

Database export

Exports all active IP addresses into a specified database or CSV text file

Integration with a SQL database for customer network management applications, enhanced reporting capabilities on address usage, and the security of a SQL database with referential integrity

Graphical and command line interfaces

Both the GUI and CLI can be used to configure and monitor Network Registrar.

Flexibility. Ability to use the interface best suited to the task or user.

Multithreaded

The DNS and DHCP servers can perform multiple tasks at the same time.

Improved performance and prevents DNS brownouts, takes advantage of multi-CPU systems.

Remote configuration and monitoring

Both GUI and CLI can be run remotely.

Saves time and allows for central configuration and management.

Reports and data exports

Can import and export data in a variety of formats and reports. Both detailed and summary address data can be exported in comma-delimited format, which can be easily imported into databases and spreadsheets.

Supports integration with existing databases. Supports tracking of address space utilization.

SNMP Notification

Warns administrators of error conditions and possible problems with the DNS and DHCP servers.

Early alerts to problems conditions and a way to set thresholds in the event of increased demands.

Web browser reporting

Runs server status, address usage, lease status, and connection status between main and backup DHCP servers.

An easy way to monitor the status of Network Registrar.

Feature	Description	Benefit
DNS Server
Classless in-addr.arpa zones	Supports use of the best practices described in RFC 2317. (Note: Network Registrar does not automatically generate the large number of alias records suggested in the RFC)	Helps support a wide variety of network topologies and DNS zone structures.
DNS subzone hiding	The DNS server can hide the subzone hierarchy for all zones delegated from a server. When enabled, the DNS server will not transfer NS and SOA records for a subzone during a zone transfer. Standard DNS queries continue to work.	Hides sensitive information about the topology of the network and devices on the network.
Dynamic DNS Updates	Allows DNS clients and DHCP servers to dynamically update DNS with new IP addresses and DNS name mappings. (RFC 2136) Network Registrar is the only DNS/DHCP product that implements dynamic DNS updates using this standard protocol.	Automatically registers clients in DNS and eliminates DNS management overhead.
Import zone files	Allows import of DNS information in the BIND zone file format; either individual files or all files specified in a named.boot file.	Speeds migration from BIND to Network Registrar.
Incremental zone transfers	Transfers only the incremental changes in a DNS zone during a zone transfer. Network Registrar is the only DNS server to support Incremental Zone Transfers. (RFC 1995)	Dramatically reduces time and bandwidth required to propagate DNS updates throughout a network. Particularly valuable if updates must traverse expensive WAN links
Internal root	Allows configuration of a DNS server as an internal root server.	Supports IP networks that are not connected to the Internet.
Interoperable with BIND	Interoperates with BIND and other RFC-compliant DNS servers. Network Registrar can be primary to a BIND secondary and vice-versa.	Supports mixed environments and a phased migration from BIND.
Notify	Primary DNS server notifies secondary DNS servers of changes to zone information. (RFC 1996)	Speeds up the propagation of dynamic DNS information.
Persistent cache	DNS cache data is stored in indexed disk files. Controls the amount of physical memory used by the DNS server. Preserves DNS cache data across system or server restarts.	Improves performance and reduces amount of memory used by the DNS server. Prevents thrashing which is caused when the DNS server consumes all physical memory.
Preconfigured root server	Preconfigured with the names and addresses of the Internet root name servers. Can be updated or overridden if needed.	Speeds and simplifies installation and configuration.
Resolution exception (Selective Forwarding)	Selectively forwards DNS queries for specified domains to internal DNS servers rather than recursively querying the root name servers on the Internet and external DNS servers.	Allows DNS to work among subsidiaries (intranets) or trading partners (extranets) without using the Internet, and thus improving network privacy.
Round-robin	If one name owns multiple A records (address records), the order of the records is rotated in successive queries for that name.	Provides a rudimentary form of load balancing. (Note: Cisco Local Directors and Distributed Director are superior solutions for load balancing)
SRV records	Supports SRV records, including dynamic DNS update of SRV records. ("Experimental" RFC 2052)	Windows 2000 compatibility. Microsoft has identified this feature as required for DNS servers in a Windows 2000/Active Directory environment.
Subnet sorting	When the DNS resolver (client), DNS server, and target are all on the same subnet, and the target has multiple addresses (A records), the server will list, in the reply, the address on the common subnet first.	CDDM compatibility feature
DHCP Server
BOOTP and Dynamic BOOTP	Supports BOOTP, which assigns addresses and configuration information to clients based on the client's MAC address and Dynamic BOOTP, which dynamically assigns IP addresses and shares an IP address pool with the DHCP server.	Supports older BOOTP clients, including many network printers
Class of service (client and client-class)	Supports customization of IP address, DHCP options, and fully-qualified domain name based on client's M AC address. Similar clients can be grouped into classes, and customization applied to the class. Can deny addresses to clients or classes	Supports the integration of CNR with a variety of network infrastructure applications Supports integration with CiscoAssure Policy Networking Supports DOCSIS cable modems
DHCP Custom Options	Allows configuration of new DHCP options	Flexibility in supporting options required by custom DHCP clients, or options standardized between revisions of Cisco Network Registrar
DHCP Option Validity	Compliance with RFC 2132.	Ensures standard option definition.
DHCP relay agent option	Supports the DHCP relay agent option, as specified in draft-ietf-dhc-agent-options.	Supports DOCSIS modems
DOCSIS modem support	Includes features needed by DOCSIS modems. These include: Support for relay agent option Class of service (allows DHCP server to distinguish between a DOCSIS modem and a user device, and configure each correctly) Support for non-requested options (return specified options to modems even if they don't request them)	Supports data-over-cable service providers
Dynamic DNS updates	DHCP server updates the DNS server with two records each in the forward and reverse zones. The forward zone receives an A record (Name and IP address) and a TXT record with the client ID (client ID = MAC address for Microsoft clients). The reverse zone receives a PTR record (IP address and name) and a TXT record with the client ID. Uses RFC 2136 Dynamic DNS Update Protocol	Automatically registers DHCP clients in DNS and eliminates DNS management overhead.
Extension points	Allows custom handling of individual DHCP packets as the DHCP server processes them. Extensions can be written in TCL scripting language or C, C++ compiled languages.	Supports additional levels of customization of individual DHCP clients.
Failover	Allows redundant DHCP servers to provide leases in the event of server failure	Provides a high-availability DHCP service. Clients requesting leases need not know or care which server is responding to their requests for leases.
Flexible name options	Supports a variety of techniques for selecting DNS names: As requested by client (end-user controlled) As specified in directory entry for client Synthesized from MAC address	Flexibility
LDAP directory support	Can read client information from an LDAP directory; can update the directory with lease data.	Supports DEN Supports integration with other network infrastructure applications
Multiple network interfaces	Supports DHCP server systems with multiple network interfaces.	Reduces network traffic on multiple network segments.
NetWare Options	Supports the NetWare options in RFCs 2241 and 2242.	Supports customers with NetWare
PING before offering lease	Before the DHCP server offers an IP address to a DHCP client, the DHCP server pings the network.	Prevents duplicate IP address assignments.
Secondary Subnets	Allows administrators to create DHCP address pools (scopes) that have addresses from multiple logical subnets that are on the same physical network.	Supports numerous network configurations and allows networks to be easily renumbered.
Supports all DHCP allocation methods	Supports all three allocation methods specified in RFC 2131: Automatic (permanent lease) Dynamic (temporary lease) Manual (reserved address)	Flexibility and standards support
Utilization alerts	Generates e-mail notices if the percentage or number of available addresses on one or more subnets falls below a configurable threshold	Alerts administrators of impending problems, allowing timely corrective action
Variable-length subnet masks	Address pools for different IP subnets can have different subnet masks.	Allows for flexible addressing schemes including OSPF configurations.
Registrar Architecture and User Interfaces
Command line interface	All aspects of Network Registrar can be configured with the CLI.	Repetitive tasks can be automated with scripts. Configuration can be integrated with other network infrastructure applications.
Database export	Exports all active IP addresses into a specified database or CSV text file	Integration with a SQL database for customer network management applications, enhanced reporting capabilities on address usage, and the security of a SQL database with referential integrity
Graphical and command line interfaces	Both the GUI and CLI can be used to configure and monitor Network Registrar.	Flexibility. Ability to use the interface best suited to the task or user.
Multithreaded	The DNS and DHCP servers can perform multiple tasks at the same time.	Improved performance and prevents DNS brownouts, takes advantage of multi-CPU systems.
Remote configuration and monitoring	Both GUI and CLI can be run remotely.	Saves time and allows for central configuration and management.
Reports and data exports	Can import and export data in a variety of formats and reports. Both detailed and summary address data can be exported in comma-delimited format, which can be easily imported into databases and spreadsheets.	Supports integration with existing databases. Supports tracking of address space utilization.
SNMP Notification	Warns administrators of error conditions and possible problems with the DNS and DHCP servers.	Early alerts to problems conditions and a way to set thresholds in the event of increased demands.
Web browser reporting	Runs server status, address usage, lease status, and connection status between main and backup DHCP servers.	An easy way to monitor the status of Network Registrar.

Cisco Network Registrar Documentation Roadmap

The Cisco Network Registrar documentation set consists of the following books:

Getting Started with Network Registrar---A quick guide that describes how to configure the Network Registrar DNS and DHCP servers
Network Registrar GUI User's Guide---A user's guide that describes how to use the Network Registrar graphical user interface (GUI) to configure and maintain the DNS and DHCP servers
Network Registrar CLI User's Guide---A user's guide that describes how to use the Network Registrar command line interface (CLI) to configure and maintain the DNS and DHCP servers
Network Registrar CLI Reference Guide---A reference guide that describes all the nrcmd commands that are used to configure and maintain the DNS and DHCP servers
Network Registrar Concepts Guide---An overview guide that describes the Network Registrar features

If you are using the GUI to administer Network Registrar, you should consult the Network Registrar Concepts Guide to learn about the concepts, and the Network Registrar GUI User's Guide to learn how to configure specific features for your site.

If you are using the CLI to administer Network Registrar, you should consult the Network Registrar Concepts Guide to learn about the concepts, and the Network Registrar CLI User's Guide, and the Network Registrar CLI Reference Guide to learn how to configure specific features for your site.

Table 1-2 lists the DNS features and the documentation that contain information about them.

Table 1-2: Locations of DNS Features in Documentation

Feature GUI UG CLI UG CLI Ref Concepts

DNS subzone hiding

Chapter 2

dns hide-subzones

Dynamic updates

Chapter 1

Chapter 3

zone dynamic/scope dns-zone-name

Import Zone files

Chapter 2

Chapter 3

import

Chapter 4

Internal Root

Chapter 2

Chapter 3

dns add RootHint

IXFR

Chapter 2

Chapter 3

dns ixfr-enable

NOTIFY

Chapter 2

Chapter 3

dns notify

Preconfigured root server

Chapter 2

Chapter 3

Removal of dynamic resource records

zone removeDynRR

Resolution Exception

Chapter 2

Chapter 3

dns addException

Round-robin

Chapter 2

Chapter 3

dns round-robin

Specification of forward and reverse zones

Chapter 2

Chapter 3

dns addForwarder

zone

SRV records

Appendix A

Appendix A

zone add Host

Subnet sorting

Chapter 2

Chapter 3

dns subnet-sorting

Feature	GUI UG	CLI UG	CLI Ref	Concepts
DNS subzone hiding	Chapter 2		dns hide-subzones
Dynamic updates	Chapter 1	Chapter 3	zone dynamic/scope dns-zone-name
Import Zone files	Chapter 2	Chapter 3	import	Chapter 4
Internal Root	Chapter 2	Chapter 3	dns add RootHint
IXFR	Chapter 2	Chapter 3	dns ixfr-enable
NOTIFY	Chapter 2	Chapter 3	dns notify
Preconfigured root server	Chapter 2	Chapter 3
Removal of dynamic resource records			zone removeDynRR
Resolution Exception	Chapter 2	Chapter 3	dns addException
Round-robin	Chapter 2	Chapter 3	dns round-robin
Specification of forward and reverse zones	Chapter 2	Chapter 3	dns addForwarder zone
SRV records	Appendix A	Appendix A	zone add Host
Subnet sorting	Chapter 2	Chapter 3	dns subnet-sorting

Table 1-3 lists the DHCP features and the books that contain information about them.

Table 1-3: Locations of DHCP Features in Documentation

Feature GUI UG CLI UG CLI Ref Concepts

All DHCP lease allocation methods

Chapter 3

Chapter 4

lease

BOOTP and Dynamic BOOTP

Chapter 3

Chapter 4

scope bootp

Class of Service

Chapter 3

Chapter 4

client-class
and client

Chapter 2

DHCP custom options

Chapter 3

Chapter 4

custom-option

DHCP option validity

Appendix C

Appendix C

DHCP relay agent option

Chapter 4

policy

DOCSIS modem support

Chapter 4

policy

Dynamic DNS Updates

Chapter 3

Chapter 4

dhcp

Extension points

Chapter 4

Chapter 8

Failover

Chapter 4

dhcp, scope, server

Chapter 3

Flexible name options

Chapter 3

client host-name

Chapter 2

LDAP directory support

Chapter 4

ldap

Chapter 7

Multiple Network Interfaces

Chapter 3

Chapter 4

dhcp-interface

NetWare options

Appendix B

Appendix B

policy setOption

PING before offering lease

Chapter 3

Chapter 4

scope ping-clients

Secondary subnets

Chapter 3

Chapter 4

scope

Utilization alerts

lease-
notification

Chapter 4

Variable-length subnet masks

Chapter 3

Chapter 4

scope

Feature	GUI UG	CLI UG	CLI Ref	Concepts
All DHCP lease allocation methods	Chapter 3	Chapter 4	lease
BOOTP and Dynamic BOOTP	Chapter 3	Chapter 4	scope bootp
Class of Service	Chapter 3	Chapter 4	client-class and client	Chapter 2
DHCP custom options	Chapter 3	Chapter 4	custom-option
DHCP option validity	Appendix C	Appendix C
DHCP relay agent option		Chapter 4	policy
DOCSIS modem support		Chapter 4	policy
Dynamic DNS Updates	Chapter 3	Chapter 4	dhcp
Extension points			Chapter 4	Chapter 8
Failover		Chapter 4	dhcp, scope, server	Chapter 3
Flexible name options	Chapter 3		client host-name	Chapter 2
LDAP directory support		Chapter 4	ldap	Chapter 7
Multiple Network Interfaces	Chapter 3	Chapter 4	dhcp-interface
NetWare options	Appendix B	Appendix B	policy setOption
PING before offering lease	Chapter 3	Chapter 4	scope ping-clients
Secondary subnets	Chapter 3	Chapter 4	scope
Utilization alerts			lease- notification	Chapter 4
Variable-length subnet masks	Chapter 3	Chapter 4	scope

Table 1-4 lists the Registrar architecture features and the books that contain information about them.

DHCP
Table 1-4: Locations of Registrar Architecture Features in Documentation

Feature GUI UG CLI UG CLI Ref Concepts

Remote configuration and monitoring

Chapter 4

Chapter 5

Reports and data exports

Chapter 4

export, report, and lease-notification

Chapter 4

SNMP notification

Chapter 4

trap

Chapter 5

Web browser reporting

Chapter 4

Chapter 5

Feature	GUI UG	CLI UG	CLI Ref	Concepts
Remote configuration and monitoring	Chapter 4	Chapter 5
Reports and data exports		Chapter 4	export, report, and lease-notification	Chapter 4
SNMP notification		Chapter 4	trap	Chapter 5
Web browser reporting	Chapter 4	Chapter 5

Table of Contents