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

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Updated:August 15, 2006

Document ID:13890

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Introduction

Prerequisites

Requirements

Components Used

Conventions

Configure

Network Diagram

Configurations

Verify

Troubleshoot

Related Information

Introduction

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.

Prerequisites

Requirements

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.

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 server 171.68.120.214 ! 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 40.31.1.144 255.255.255.0 ip access-group 116 in ip nat outside ip auth-proxy list_a no ip route-cache no ip mroute-cache speed auto half-duplex no mop enabled ! interface Ethernet1/0 ip address 10.14.14.14 255.255.255.0 ip nat inside ip inspect myfw in speed auto half-duplex ! !--- Interfaces deleted. ! nat pool outsidepool 40.31.1.50 40.31.1.60 netmask 255.255.255.0 ip nat inside source list 1 pool outsidepool ip nat inside source static 10.14.14.15 40.31.1.77 ip classless ip route 0.0.0.0 0.0.0.0 40.31.1.1 ip route 171.68.118.0 255.255.255.0 40.31.1.1 ip route 171.68.120.0 255.255.255.0 40.31.1.1 no ip http server ! access-list 116 permit tcp host 171.68.118.143 host 40.31.1.144 eq www access-list 116 deny tcp host 171.68.118.143 any access-list 116 deny udp host 171.68.118.143 any access-list 116 deny icmp host 171.68.118.143 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 171.68.120.214 tacacs-server key cisco ! line con 0 transport input none line aux 0 line vty 0 4 password ww ! end

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
 server 171.68.120.214
!

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 40.31.1.144 255.255.255.0
 
ip access-group 116 in
 ip nat outside
 
ip auth-proxy list_a
 no ip route-cache
 no ip mroute-cache
 speed auto
 half-duplex
 no mop enabled
!
interface Ethernet1/0
 ip address 10.14.14.14 255.255.255.0
 ip nat inside
 ip inspect myfw in
 speed auto
 half-duplex
!

 !--- Interfaces deleted.

!
nat pool outsidepool 40.31.1.50 40.31.1.60 netmask 255.255.255.0
ip nat inside source list 1 pool outsidepool
ip nat inside source static 10.14.14.15 40.31.1.77
ip classless
ip route 0.0.0.0 0.0.0.0 40.31.1.1
ip route 171.68.118.0 255.255.255.0 40.31.1.1
ip route 171.68.120.0 255.255.255.0 40.31.1.1
no ip http server
!

access-list 116 permit tcp host 171.68.118.143 host 40.31.1.144 eq www
access-list 116 deny   tcp host 171.68.118.143 any
access-list 116 deny   udp host 171.68.118.143 any
access-list 116 deny   icmp host 171.68.118.143 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 171.68.120.214
tacacs-server key cisco
!         
line con 0
 transport input none
line aux 0
line vty 0 4
 password ww
!
end