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This chapter describes the commands used to configure Port to Application Mapping (PAM). PAM allows you to customize TCP or UDP port numbers for network services or applications. PAM uses this information to support network environments that run services using ports that are different from the registered or well-known ports associated with an application.
For information on how to configure PAM, refer to the "Configuring Port to Application Mapping" chapter in the Cisco IOS Security Configuration Guide. For configuration examples using the commands in this chapter, refer to the "PAM Configuration Examples" section located at the end of the "Configuring Port to Application Mapping" chapter in the Cisco IOS Security Configuration Guide.
To establish Port to Application Mapping (PAM), use the ip port-map configuration command. Use the no form of this command to delete user-defined PAM entries.
ip port-map appl_name port port_num [list acl_num]
Syntax Description
appl_name Specifies the name of the application with which to apply the port mapping. port Indicates that a port number maps to the application. port_num Identifies a port number in the range 1 to 65535. list Indicates that the port mapping information applies to a specific host or subnet. acl_num Identifies the standard access control list (ACL) number used with PAM.
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
12.0(5)T This command was introduced.
Release
Modification
Usage Guidelines
The ip port-map command associates TCP or UDP port numbers with applications or services, establishing a table of default port mapping information at the firewall. This information is used to support network environments that run services using ports that are different from the registered or well-known ports associated with a service or application.
The port mapping information in the PAM table is one of three types:
System-defined Port Mapping
Initially, PAM creates a set of system-defined entries in the mapping table using well-known or registered port mapping information set up during the system start-up. The Cisco IOS Firewall CBAC feature requires the system-defined mapping information to function properly. System-defined mapping information cannot be deleted or changed; that is, you cannot map HTTP services to port 21 (FTP) or FTP services to port 80 (HTTP).
Table 16 list the default system-defined services and applications in the PAM table.
| Application Name | Well-known or Registered Port Number | Protocol Description |
|---|---|---|
cuseeme | 7648 | CU-SeeMe Protocol |
exec | 512 | Remote Process Execution |
ftp | 21 | File Transfer Protocol (control port) |
http | 80 | Hypertext Transfer Protocol |
h323 | 1720 | H.323 Protocol (for example, MS NetMeeting, Intel Video Phone) |
login | 513 | Remote login |
msrpc | 135 | Microsoft Remote Procedure Call |
netshow | 1755 | Microsoft NetShow |
real-audio-video | 7070 | RealAudio and RealVideo |
smtp | 25 | Simple Mail Transfer Protocol |
sql-net | 1521 | SQL-NET |
streamworks | 1558 | StreamWorks Protocol |
sunrpc | 111 | SUN Remote Procedure Call |
tftp | 69 | Trivial File Transfer Protocol |
vdolive | 7000 | VDOLive Protocol |
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Note You can override the system-defined entries for a specific host or subnet using the list option in the ip port-map command. |
User-defined Port Mapping
Network applications that use non-standard ports require user-defined entries in the mapping table. Use the ip port-map command to create default user-defined entries in the PAM table.
To map a range of port numbers with a service or application, you must create a separate entry for each port number.
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Note If you try to map an application to a system-defined port, a message appears warning you of a mapping conflict. |
Use the no form of the ip port-map command to delete user-defined entries from the PAM table.
To overwrite an existing user-defined port mapping, use the ip port-map command to associate another service or application with the specific port.
Host-specific Port Mapping
User-defined entries in the mapping table can include host-specific mapping information, which establishes port mapping information for specific hosts or subnets. In some environments, it might be necessary to override the default port mapping information for a specific host or subnet, including a system-defined default port mapping information. Use the list option for the ip port-map command to specify an ACL for a host or subnet that uses PAM.
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Note If the host-specific port mapping information is the same as existing system-defined or user-defined default entries, host-specific port changes have no effect. |
Examples
The following example provides examples for adding and removing user-defined PAM configuration entries at the firewall.
In the following example, non-standard port 8000 is established as the user-defined default port for HTTP services:
ip port-map http port 8000
The following example shows PAM entries establish a range of non-standard ports for HTTP services:
ip port-map http 8001 ip port-map http 8002 ip port-map http 8003 ip port-map http 8004
In the following example the command fails because it tries to map port 21, which is the system-defined default port for FTP, with HTTP:
ip port-map http port 21
In the following example, a specific host uses port 8000 for FTP services. ACL 10 identifies the server address (192.168.32.43), while port 8000 is mapped with FTP services:
access-list 10 permit 192.168.32.43 ip port-map ftp port 8000 list 10
In the following example, port 21, which is normally reserved for FTP services, is mapped to the RealAudio application for the hosts in list 10. In this configuration, hosts in list 10 do not recognize FTP activity on port 21.
ip port-map realaudio port 21 list 10
In the following example, the ip port-map command fails and generates an error message:
ip port-map netshow port 21
Command fail: the port 21 has already been defined for ftp by the system.
No change can be made to the system defined port mappings.
The no form of this command deletes user-defined entries from the PAM table. It has no effect on the system-defined port mappings. This command deletes the host-specific port mapping of FTP.
no ip port-map ftp port 1022 list 10
In the following example, the command fails because it tries to delete the system-defined default port for HTTP:
no ip port-map http port 80
In the following example, a specific host uses port 8000 for FTP services. ACL 10 identifies the server address (192.168.32.43), while port 8000 is mapped with FTP services.
access-list 10 permit 192.168.32.43 ip port-map ftp port 8000 list 10
In the following example, a specific subnet runs HTTP services on port 8080. ACL 50 identifies the subnet, while the PAM entry maps port 8080 with HTTP services.
access-list 50 permit 192.168.92.0 ip port-map http 8080 list 50
In the following example, a specific host runs HTTP services on port 25, which is the system-defined port number for SMTP services. This requires a host-specific PAM entry that overrides the system-defined default port mapping for HTTP, which is port 80. ACL 15 identifies the host address (192.168.33.43), while port 25 is mapped with HTTP services.
access-list 15 permit 192.168.33.43 ip port-map http port 25 list 15
In the following example, the same port number is required by different services running on different hosts. Port 8000 is required for HTTP services by host 192.168.3.4, while port 8000 is required for Telnet services by host 192.168.5.6. ACL 10 and ACL 20 identify the specific hosts, while PAM maps the ports with the services for each ACL.
access-list 10 permit 192.168.3.4 access-list 20 permit 192.168.5.6 ip port-map http port 8000 list 10 ip port-map http ftp 8000 list 20
Related Commands
show ip port-map Displays the PAM information.
Command
Description
To display the Port to Application Mapping (PAM) information, use the show ip port-map privileged EXEC command.
show ip port-map [appl_name | port port_num]
Syntax Description
appl_name Specifies the name of the application to which to apply the port mapping. port port_num Specifies the alternative port number that maps to the application.
Command Modes
Privileged EXEC
Command History
12.0(5)T This command was introduced.
Release
Modification
Usage Guidelines
Use this command to display the port mapping information at the firewall, including the system-defined and user-defined information. Include the application name to display the list of entries by application. Include the port number to display the entries by port.
Examples
The following is sample output for the show ip port-map command, including system-defined mapping information:
show ip port-map Default mapping: vdolive port 7000 system defined Default mapping: sunrpc port 111 system defined Default mapping: netshow port 1755 system defined Default mapping: cuseeme port 7648 system defined Default mapping: tftp port 69 system defined Default mapping: real-audio-video port 7070 system defined Default mapping: streamworks port 1558 system defined Default mapping: ftp port 21 system defined Default mapping: h323 port 1720 system defined Default mapping: smtp port 25 system defined Default mapping: http port 80 system defined Default mapping: msrpc port 135 system defined Default mapping: exec port 512 system defined Default mapping: login port 513 system defined Default mapping: sql-net port 1521 system defined Default mapping: tftp port 70 user defined Host specific: ftp port 1000 in list 10 user defined Host specific: netshow port 70 in list 10 user defined Host specific: smtp port 70 in list 50 user defined
The following example shows the port mapping information for FTP services:
sh ip port-map ftp Default mapping: ftp port 21 system defined Host specific: ftp port 1000 in list 10 user defined
The following example shows the ports associated with the NetShow application, including both the default and host-specific port mapping information:
sh ip port-map netshow Default mapping: netshow port 1755 system defined Host specific: netshow port 21 in list 10 user defined
The following example shows the applications associated with port 69, including both the default and host-specific port mapping information:
sh ip port-map port 69 Default mapping: tftp port 69 user defined Host specific: netshow port 69 in list 50 user defined Host specific: smtp port 69 in list 10 user defined
Related Commands
ip port-map Establishes PAM.
Command
Description
Posted: Thu Aug 10 17:29:49 PDT 2000
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