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ssh from macos disable cli completion

alain_richard
Level 1
Level 1

Hi,

 

I am just about to setup new IOS XR devices (ASR 9901 and NCS 540) and I am encountering a silly problem : when connecting to the devices with SSH from a mac os x client, all the terminal keys are disabled and not recognized (arrow keys, cli completion, ...).

 

With the same terminal client and using the serial console, the problem is not present.

 

Also from the same terminal client, if I ssh to a linux host and then ssh to the XR device, the problem is not present.

 

So it seams that using a SSH session from a macos X client trigger something on the IOS XR side that disable all vt100 key recognition.

 

The problem is not present when accessing classical IOS devices.

 

Anyone has a clue about that silly problem ?

 

Alain

1 Reply 1

alain_richard
Level 1
Level 1

When I connect, I get the following errors :

mbagr:.ssh arichard$ ssh root@192.168.240.120
Password:
Warning: No xauth data; using fake authentication data for X11 forwarding.
X11 forwarding request failed on channel 0
PTY allocation request failed on channel 0

So the problem here seam to be "PTY allocation request failed on channel 0".

Looking at my .ssh config file, I found out that I was using the following options :

host *
protocol 2
ForwardX11 yes
ForwardX11Trusted yes

After disabling ForwardX11 and ForwardX11Trusted, the problem disappeared :

mbagr:.ssh arichard$ ssh root@192.168.240.120
Password:
RP/0/RSP0/CPU0:phoebe10#

and I get all the CLI functionnalities !

 

So the problem was with the X11 forwarding options.

 

Disabling it is no longer a big problem X11 is not used any longer, but this is a strange behaviour on the Cisco side that was not present on the IOS or IOS XE side.

 

Alain 

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