Cisco Access Servers

The idea behind Cisco access servers is to allow you to connect to the console port of multiple routers and switches so you can perform disaster recovery in case the device loses network connectivity.

For home labs though, we can use the same principle to allow us to configure multiple devices through one connection or terminal session.

You have three choices when considering a Cisco access server – 2509, 2511 or a NM16AS/NM32AS (seen left) which is a card you can slot into modular routers. The 2509 gives you 8 ports with which to connect an octal cable which is 8 console leads in one. The 2511 has 16 and the NM32 has 32.

If you want to connect the ports on your access server to the console ports on your routers you will also need one or more Cisco octal cables which you can also buy easily from eBay suppliers.

Each console cable on the octal cable is usually numbered from 1 to 8 and when you come to configure you access server you use port numbers 2001 for cable 1, 2002 for cable 2 and so on. If you plug a second octal cable in then you start on port 2009.

Please double check on the access servers that you have plugged the first cable into asynch ports numbered 1-8. Please also ensure that you plug the asynch side in the right way up and screw it in securely.

Once you have done this you will need to put a configuration onto the access server. Here is a basic configuration which you can alter once you gain more knowledge and confidence.

The ip host command tells the router to allow you to connect to each host from the access server by the hostname such as R1 instead of tying out the full port and IP address.

Current configuration : 1322 bytes

!

version 12.3
service timestamps debug uptime
service timestamps log uptime
service password-encryption
service tcp-small-servers
!
hostname 2511
!
boot-start-marker
boot-end-marker
!
enable password 7 06360E325F59060B017858
!
no aaa new-model
ip subnet-zero
no ip domain lookup
ip host R1 2001 192.168.100.20
ip host R22002 192.168.100.20
ip host R3 2003 192.168.100.20
ip host R4 2004 192.168.100.20
ip host Sw1 2005 192.168.100.20
!
!
interface Ethernet0
ip address 192.168.100.20 255.255.255.0
!
interface Serial0
no ip address
shutdown
!
no ip http server
ip classless
ip route 0.0.0.0 0.0.0.0 192.168.100.1
!
line con 0
line 1 16
session-timeout 20
exec-timeout 0 0
no exec
transport input all
line aux 0
transport input all
line vty 0 4
password 7 13351601181B756A6061
login
!
end
2511#

You can now either connect to the devices from your laptop putty session with ip address 192.168.100.20 2001 (for router 1) or you can connect directly to the access server and at the Router# prompt type R1:

2511#R1

R1#

Videos

Here are two YouTube videos I filmed which will help you set everything up.