Reverse Telnet on Catalyst 8500 (no Aux port)

[Tyson Joachims]

Just recently swapped out a C3200 with a C8500. The C3200 had an Aux port that we could use reverse telnet to access the modem which would dial another modem at a remote location and enter the router there as a backup connection (if the VPN to that remote location failed we could troubleshoot the cause.) The C8500 does not have a physical Aux port although the CLI shows one. I am trying to figure out how to accomplish the same goal by using the console port.

Here shows the "show line"

99Router(config)#do show line
   Tty Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   Int
*     0 CTY              -    -      -    -    -      0       0     0/0       -
      1 AUX   9600/9600  -    -      -    -    -      0       0     0/0       -
*     2 VTY              -    -      -    -    -     46       0     0/0       -
      3 VTY              -    -      -    -    -      7       0     0/0       -
      4 VTY              -    -      -    -    -      0       0     0/0       -
      5 VTY              -    -      -    -    -      0       0     0/0       -
      6 VTY              -    -      -    -    -      0       0     0/0       -

The cosole (Tty 0) is already in use by default so I cannot reverse telnet using x.x.x.x:2000

Any ideas how to use reverse telnet when you have no aux port? Or is there a physical aux port on the C8500 and I'm just totally blind?

[MHM Cisco World]

I think since you have AUX you can config reverse telnet 
1 AUX   9600/9600  -    -      -    -    -      0       0     0/0  

please find below link for example how you can config  
https://www.cisco.com/c/en/us/support/docs/dial-access/asynchronous-connections/5466-comm-server.html

[Tyson Joachims]

I've looked at that page but it references "A terminal server is a router with multiple, low speed, asynchronous ports that are connected to other serial devices" but the 8500 has none of these (from what I can tell). The weird parts is the fact that the configuration shows an Aux port but there is not a physical aux port on the Catalyst 8500. Is there's a way to make an existing interface (serial or ethernet) emulate an Aux interface or can the 8500 just not do reverse telnet?

[Richard Burts]

I do not have experience with this model. But my guess is that the config shows line aux 0 because it is part of the standard template for parsing the configuration.

If there is no physical port then there is no way to physically connect to the modem. I think you will need to find a different way to connect to the other site.

[Richard Burts]

I see numerous examples of things like this in configs. For example I see this in many config

multilink bundle-name authenticated

when there is absolutely no multilink capability in the router.