12-02-2008 01:10 PM - edited 03-06-2019 02:46 AM
Let's say I have two switches on two different floors of a building that have a trunked fiber connection. The one switch I have the console cable connected to a serial KVM where I can get in out of band and console to the switch, but because the fiber connection got severed I can't telnet to the other switch but I have to get into it. can I connect the Aux port from one switch to the console port of the other so I can telent in that way? or is there another way?
Mike
12-02-2008 01:19 PM
hello Mike,
unfortunately lan switches (modern ones at least) usually miss an aux port but the answer is yes a connection aux to console can be configured and the one with the aux acts as a terminal server providing access to the other device's console.
I did this successfully with routers.
have you alredy tried a shut/no shut cycle on the switch you can reach of the fiber link port ?
Hope to help
Giuseppe
12-02-2008 01:30 PM
I want to set this up to avoid this problem. We had something simular happen so I wanted to see if this was possible. Can you send me how I have to have this configured? or direct me to some documentation.
Thanks,
Mike
12-02-2008 09:43 PM
Hello Mike,
first of all you need to identify the line number associated to the aux port:
RT-RM-TLD066-VPN-2#sh line | inc AUX
65 AUX 9600/9600 - - - - - 7 4397 0/1259 -
RT-RM-TLD066-VPN-2#
the number in my case is 65. This is useful to configure for reverse telnet
ip host new-vpn-2 2065 xx.xx.xx.253
the tcp port is 2000 + aux.linenumber
then you need to configure the aux port:
line aux 0
no exec
transport input all
transport output all
(I have also AAA authentication)
if I telnet to the host name I have to authenticate again and then I see the other router console
RT-RM-TLD066-VPN-2#sh users
Line User Host(s) Idle Location
65 aux 0 g.larosa incoming 00:02:04 new-vpn-2
66 vty 0 g.larosa new-vpn-2 00:02:05 10.55.49.56
* 67 vty 1 g.larosa idle 00:00:00 10.55.49.56
from a second vty 1, line 67 I can see that vty0 is connected to the host and to aux
To close it I usually use clear line vty.line.number from the second telnet session
you need a loopback on the router that acts as the terminal server: the masked address above is actually the ip address of a loopback.
Hope to help
Giuseppe
12-03-2008 05:51 AM
I will try this out today...I hope :-)
I will post how this turns out.
Thanks.
Mike
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