Cisco IOS Firewall

Auth-proxy Authentication Inbound (Cisco IOS Firewall - Routers/Switches and NAT) Configuration Example

Document ID: 13890

Updated: Aug 15, 2006



This sample configuration initially blocks traffic from external hosts to all devices on the internal network until browser authentication is performed using authentication proxy. After authorization, the access list passed down from the server (permit tcp|ip|icmp any any) adds dynamic entries to access list 116 that temporarily allow access from the external PC to the internal network.

Note: The AAA configuration used in this document is also applicable to Catalyst switches that run Cisco IOS® software.



There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

  • Cisco IOS Software Release 12.2.23

  • Cisco 3640 router

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.


Refer to the Cisco Technical Tips Conventions for more information on document conventions.


In this section, you are presented with the information to configure the features described in this document.

Note: Use the Command Lookup Tool (registered customers only) to obtain more information on the commands used in this section.

Network Diagram

This document uses this network setup:



This document uses this configuration:

  • Cisco 3640 Router

Cisco 3640 Router
Current configuration:
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
hostname sec-3640

aaa new-model
aaa group server tacacs+ RTP

aaa authentication login default group RTP none
aaa authorization exec default group RTP none
aaa authorization auth-proxy default group RTP
enable secret 5 $1$pqRI$3TDNFT9FdYT8Sd/q3S0VU1
enable password ww
ip subnet-zero
ip inspect name myfw cuseeme timeout 3600
ip inspect name myfw ftp timeout 3600
ip inspect name myfw http timeout 3600
ip inspect name myfw rcmd timeout 3600
ip inspect name myfw realaudio timeout 3600
ip inspect name myfw smtp timeout 3600
ip inspect name myfw sqlnet timeout 3600
ip inspect name myfw streamworks timeout 3600
ip inspect name myfw tftp timeout 30
ip inspect name myfw udp timeout 15
ip inspect name myfw tcp timeout 3600
ip inspect name myfw vdolive

ip auth-proxy auth-proxy-banner
ip auth-proxy auth-cache-time 10
ip auth-proxy name list_a http
ip audit notify log
ip audit po max-events 100
interface Ethernet0/0
 ip address
ip access-group 116 in
 ip nat outside
ip auth-proxy list_a
 no ip route-cache
 no ip mroute-cache
 speed auto
 no mop enabled
interface Ethernet1/0
 ip address
 ip nat inside
 ip inspect myfw in
 speed auto

!--- Interfaces deleted.

nat pool outsidepool netmask
ip nat inside source list 1 pool outsidepool
ip nat inside source static
ip classless
ip route
ip route
ip route
no ip http server

access-list 116 permit tcp host host eq www
access-list 116 deny   tcp host any
access-list 116 deny   udp host any
access-list 116 deny   icmp host any
access-list 116 permit icmp any any
access-list 116 permit tcp any any
access-list 116 permit udp any any
dialer-list 1 protocol ip permit
dialer-list 1 protocol ipx permit
tacacs-server host
tacacs-server key cisco
line con 0
 transport input none
line aux 0
line vty 0 4
 password ww


Refer to Important Information on Debug Commands before you issue debug commands.

Refer to Troubleshooting Authentication Proxy for command and troubleshooting information.


There is currently no specific troubleshooting information available for this configuration.

Related Information

Updated: Aug 15, 2006
Document ID: 13890