Cisco IOS Firewall

Authentication Proxy Authentication Inbound - No Cisco IOS Firewall or NAT Configuration

Document ID: 13885

Updated: Aug 15, 2006



This sample configuration initially blocks traffic from a host device (at on the external network to all devices on the internal network until you perform browser authentication with the use of authentication proxy. The access list passed down from the server (permit tcp|ip|icmp any any) adds dynamic entries post-authorization to access list 115 that temporarily allow access from the host device to the internal network.



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 12.0.7.T

  • Cisco 3640 router

Note: The ip auth-proxy command was introduced in Cisco IOS Software Release 12.0.5.T. This configuration was tested with Cisco IOS Software Release 12.0.7.T.

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:

3640 Router
Current configuration:
version 12.0
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
hostname security-3640

!--- Turn on authentication.

aaa new-model

!--- Define the server group and servers for TACACS+ or RADIUS.

aaa group server tacacs+|radius RTP

!--- Define what you need to authenticate.

aaa authentication login default group RTP none
aaa authorization exec default group RTP none
aaa authorization auth-proxy default group RTP
enable secret 5 $1$H9zZ$z9bu5HMy4NTtjsvIhltGT0
enable password ww
ip subnet-zero

!--- You want the router name to appear as banner.

ip auth-proxy auth-proxy-banner

!--- You want the access-list entries to timeout after 10 minutes.

ip auth-proxy auth-cache-time 10

!--- You define the list-name to be associated with the interface.

ip auth-proxy name list_a http
ip audit notify log
ip audit po max-events 100
cns event-service server
process-max-time 200
interface FastEthernet0/0
 ip address
 no ip directed-broadcast
 no mop enabled
interface FastEthernet1/0
 ip address

!--- Apply the access-list to the interface.

ip access-group 115 in
 no ip directed-broadcast

!--- Apply the auth-proxy list-name.

 ip auth-proxy list_a
ip classless
ip route

!--- Turn on the http server and authentication.

ip http server
ip http authentication aaa

!--- This is our access-list for auth-proxy testing -
!--- it denies only one host,, access - to minimize disruption
!--- to the network during testing.

access-list 115 permit tcp host host eq www
access-list 115 deny   icmp host any
access-list 115 deny   tcp host any
access-list 115 deny   udp host any
access-list 115 permit udp any any
access-list 115 permit tcp any any
access-list 115 permit icmp any any
dialer-list 1 protocol ip permit
dialer-list 1 protocol ipx permit

!--- Define the server(s).

tacacs-server host
tacacs-server key cisco
radius-server host
radius-server key cisco
line con 0
 transport input none
line aux 0
line vty 0 4
 password ww


There is currently no verification procedure available for this configuration.


This section provides information you can use in order to troubleshoot your configuration.

For these commands, along with other troubleshooting information, refer to Troubleshooting Authentication Proxy.

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

Related Information

Updated: Aug 15, 2006
Document ID: 13885