Reverse Telnet: Aux/Console

Carlo Zaina · ‎03-17-2009

Hi.

Router R1 has some trouble during the boot, so i wish to connect via R2's Auxiliary port to R1's console port.

What's the configuration for the Aux port on R2?

So far i implemented this:

line aux 0

modem InOut

transport input all

transport output all

#show line

5 AUX 9600/9600 - inout

If i telnet to R2's Loopback ip address with port number 2005 i get an "open" and nothing else.

Also, for the connection, what kind of cable do i need? I read around "flat crossover cable": an ethernet cross cable might work?

Thank you

paolo bevilacqua · ‎03-17-2009

No, ethernet crossover will not work. You need the "flat crossover cable" shipped with every router.

Carlo Zaina · ‎03-17-2009

Honestly, i have seen only rollover cables, ethernet cables and console cables shipped with the routers.

I was trying to figure out the pin layout...

paolo bevilacqua · ‎03-17-2009

Rollover cable is what we're talking about. 1-8 2-7 3-6 4-5.

Carlo Zaina · ‎03-18-2009

Perfect.

Pin Layout:

1 2 3 4 5 6 7 8

| | | | | | | |

8 7 6 5 4 3 2 1

So, in order to be able to connect from the R2's Auxiliary port to the R1's Console port, what else should i do?

paolo bevilacqua · ‎03-18-2009

Nothing else. Remember to rate useful posts with the scrollbox below.

Carlo Zaina · ‎03-19-2009

Well, i am still unable to connect.

R1's Config

line aux 0

modem InOut

transport preferred telnet

transport input all

transport output all

#show line

* 1 1 AUX 9600/9600 - inout

#sh ip interface brief

Loopback100 192.168.254.1 YES manual up up

(C1841-IPBASEK9-M), Version 12.4(20)T1

R2's Config

line con 0

logging synchronous

transport preferred telnet

transport output all

(C1841-IPBASEK9-M), Version 12.4(20)T1

However:

R1#telnet 192.168.254.1 1

Trying 192.168.254.1, 1 ...

% Connection refused by remote host

Any further tip?

paolo bevilacqua · ‎03-19-2009

You should connect to port 2005.

Beside that, sometime the line remains taken from previous use, do "clear line 5" on R1.

Carlo Zaina · ‎03-19-2009

Suddenly, after the 4th attempt, it worked.

i added a no exec to the line aux 0 configuration.