Auth-proxy Authentication Outbound (Cisco IOS Firewall and NAT) Configuration

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Updated:July 3, 2007

Document ID:13889

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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 a host device (at 10.31.1.47) on the internal network to all devices on the Internet 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 116 that temporarily allow access from that device to the Internet.

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

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.

3640 Router
Current configuration: ! version 12.2 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname security-3640 ! aaa new-model aaa group server tacacs+ RTP server 171.68.118.115 ! aaa authentication login default local group RTP none aaa authorization exec default group RTP none aaa authorization auth-proxy default group RTP enable secret 5 $1$vCfr$rkuU6HLmpbNgLTg/JNM6e1 enable password ww ! username john password 0 doe ! 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 ! process-max-time 200 ! interface Ethernet0/0 ip address 10.31.1.150 255.255.255.0 ip access-group 116 in ip nat inside ip inspect myfw in ip auth-proxy list_a no ip route-cache no ip mroute-cache ! interface Ethernet1/0 ip address 11.11.11.11 255.255.255.0 ip access-group 101 in ip nat outside ! ip nat pool outsidepool 11.11.11.20 11.11.11.30 netmask 255.255.255.0 ip nat inside source list 1 pool outsidepool ip classless ip route 0.0.0.0 0.0.0.0 11.11.11.1 ip route 171.68.118.0 255.255.255.0 10.31.1.1 ip http server ip http authentication aaa ! access-list 1 permit 10.31.1.0 0.0.0.255 access-list 101 deny ip 10.31.1.0 0.0.0.255 any access-list 101 deny ip 127.0.0.0 0.255.255.255 any access-list 101 permit icmp any 11.11.11.0 0.0.0.255 unreachable access-list 101 permit icmp any 11.11.11.0 0.0.0.255 echo-reply access-list 101 permit icmp any 11.11.11.0 0.0.0.255 packet-too-big access-list 101 permit icmp any 11.11.11.0 0.0.0.255 time-exceeded access-list 101 permit icmp any 11.11.11.0 0.0.0.255 traceroute access-list 101 permit icmp any 11.11.11.0 0.0.0.255 administratively-prohibited access-list 101 permit icmp any 11.11.11.0 0.0.0.255 echo access-list 116 permit tcp host 10.31.1.47 host 10.31.1.150 eq www access-list 116 deny tcp host 10.31.1.47 any access-list 116 deny udp host 10.31.1.47 any access-list 116 deny icmp host 10.31.1.47 any access-list 116 permit tcp 10.31.1.0 0.0.0.255 any access-list 116 permit udp 10.31.1.0 0.0.0.255 any access-list 116 permit icmp 10.31.1.0 0.0.0.255 any access-list 116 permit icmp 171.68.118.0 0.0.0.255 any access-list 116 permit tcp 171.68.118.0 0.0.0.255 any access-list 116 permit udp 171.68.118.0 0.0.0.255 any dialer-list 1 protocol ip permit dialer-list 1 protocol ipx permit ! tacacs-server host 171.68.118.115 tacacs-server key cisco radius-server host 171.68.118.115 auth-port 1645 acct-port 1646 radius-server key cisco ! line con 0 transport input none line aux 0 line vty 0 4 exec-timeout 0 0 password ww ! end

Current configuration:
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname security-3640
!
aaa new-model
aaa group server tacacs+ RTP
 server 171.68.118.115
!
aaa authentication login default local group RTP none
aaa authorization exec default group RTP none
aaa authorization auth-proxy default group RTP
enable secret 5 $1$vCfr$rkuU6HLmpbNgLTg/JNM6e1
enable password ww
!
username john password 0 doe
!
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
!
process-max-time 200
!
interface Ethernet0/0
 ip address 10.31.1.150 255.255.255.0
 ip access-group 116 in
 ip nat inside
 ip inspect myfw in
 ip auth-proxy list_a
 no ip route-cache
 no ip mroute-cache
!
interface Ethernet1/0
 ip address 11.11.11.11 255.255.255.0
 ip access-group 101 in
 ip nat outside
!         
ip nat pool outsidepool 11.11.11.20 11.11.11.30 netmask 255.255.255.0
ip nat inside source list 1 pool outsidepool
ip classless
ip route 0.0.0.0 0.0.0.0 11.11.11.1
ip route 171.68.118.0 255.255.255.0 10.31.1.1
ip http server
ip http authentication aaa
!
access-list 1 permit 10.31.1.0 0.0.0.255
access-list 101 deny   ip 10.31.1.0 0.0.0.255 any
access-list 101 deny   ip 127.0.0.0 0.255.255.255 any
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 unreachable
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 echo-reply
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 packet-too-big
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 time-exceeded
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 traceroute
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 administratively-prohibited
access-list 101 permit icmp any 11.11.11.0 0.0.0.255 echo
access-list 116 permit tcp host 10.31.1.47 host 10.31.1.150 eq www
access-list 116 deny   tcp host 10.31.1.47 any
access-list 116 deny   udp host 10.31.1.47 any
access-list 116 deny   icmp host 10.31.1.47 any
access-list 116 permit tcp 10.31.1.0 0.0.0.255 any
access-list 116 permit udp 10.31.1.0 0.0.0.255 any
access-list 116 permit icmp 10.31.1.0 0.0.0.255 any
access-list 116 permit icmp 171.68.118.0 0.0.0.255 any
access-list 116 permit tcp 171.68.118.0 0.0.0.255 any
access-list 116 permit udp 171.68.118.0 0.0.0.255 any
dialer-list 1 protocol ip permit
dialer-list 1 protocol ipx permit
!
tacacs-server host 171.68.118.115
tacacs-server key cisco
radius-server host 171.68.118.115 auth-port 1645 acct-port 1646
radius-server key cisco
!
line con 0
 transport input none
line aux 0
line vty 0 4
 exec-timeout 0 0
 password ww
!
end