X11Forward and xauth problems

[Andrew DeFaria]

Normally I just turn on -X (or put X11Forward yes in ~/.ssh/config) but 
that usually results in a noticeable delay in logging in and the 
following error:

Warning: untrusted X11 forwarding setup failed: xauth key data not generated
Warning: No xauth data; using fake authentication data for X11 forwarding.
/usr/bin/xauth:  unable to link authority file 
/home/adefaria/.Xauthority, use /home/adefaria/.Xauthority-n
Cm-app-ldev01:

I've asked about this in the past and I think the answer was that the 
message was correct but you shouldn't worry about it. If it didn't slow 
me down I probably would just ignore it. But it slows me down. So I ssh 
instead without X11Forward turned on then, when I need to run an X 
client, I do export DISPLAY=adefaria-lt:0 and make sure that I did an 
xhost + there at least once. But now that's broken!

Adefaria-lt:xhost +
access control disabled, clients can connect from any host
Adefaria-lt:ssh cm-app-ldev01
Cm-app-ldev01:export DISPLAY=adefaria-lt:0
Cm-app-ldev01:xclock
Error: Can't open display: adefaria-lt:0
Cm-app-ldev01:

I still don't understand xauth but I've been playing with it and I can 
sometimes get it to work.

Adefaria-lt:rm ~/.Xauthority*
Adefaria-lt:ssh -X cm-app-ldev01 xclock
Warning: untrusted X11 forwarding setup failed: xauth key data not generated
Warning: No xauth data; using fake authentication data for X11 forwarding.
/usr/bin/xauth:  creating new authority file /home/adefaria/.Xauthority
Adefaria-lt:ssh -X cm-app-ldev01 xclock
Warning: untrusted X11 forwarding setup failed: xauth key data not generated
Warning: No xauth data; using fake authentication data for X11 forwarding.
/usr/bin/xauth:  unable to link authority file 
/home/adefaria/.Xauthority, use /home/adefaria/.Xauthority-n
X11 connection rejected because of wrong authentication.
Error: Can't open display: localhost:12.0
Adefaria-lt:

The first ssh to cm-app-ldev01 to run xclock works fine. Do it again and 
it fails.

Ideal solution: ssh -X works with no warnings or musings about .Xauthority.

Workable solution(s): Either that ssh -X complains about .Xauthority but 
still reliably puts up X clients or I can use xhost + and export DISPLAY.
-- 
Andrew DeFaria
http://defaria.com


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