Slow logout and hanging passwordless ssh connection

Issues related to configuring your network
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AcelaExpress
Posts: 3
Joined: 2013/03/10 22:34:17

Slow logout and hanging passwordless ssh connection

Post by AcelaExpress » 2021/08/15 16:21:01

I am running 2 VMs of Centos 8-stream in VirtualBox. Ever since I installed them if I login from my Centos 7 machine using ssh in an xterm (mate-terminal or gnome-terminal), there is an odd 3-4 second lag when logging out from Centos 8 stream. I did not have this lag when I had regular Centos 8 installed. I also do not experience this logout lag when I ssh into my Centos 7 VM.

Another oddity, if I run a passwordless ssh command like the following, I never get a prompt back. It also hangs. I do not experience this on my Centos 7 VM.

$ ssh 192.168.X.XX "uptime"
12:07:48 up 17 days, 3:30, 0 users, load average: 0.02, 0.06, 0.04
(hangs when I ssh from my Centos 7 machine to my Centos 8 Stream VM, or from a Centos 8 stream to another Centos 8 stream machine).

$ ssh 192.168.X.XX "uptime"
12:08:32 up 24 days, 3:36, 3 users, load average: 0.30, 0.60, 0.73
(exits cleanly when I ssh from my Centos 7 machine to another Centos 7 VM).

I also tried ssh -vvv and it just says the connection remains open - it never terminates until I hit CTRL-C.

Any ideas how to fix this behavior? I have looked at my bash .logout (it's empty, and I also removed it completely with no change in behavior). I looked at /etc/hosts and nothing looks suspicious, it has the default entry of 127.0.0.1. I added the machine's IP to that file and it is the same behavior.

Thanks for any ideas.

AcelaExpress
Posts: 3
Joined: 2013/03/10 22:34:17

Re: Slow logout and hanging passwordless ssh connection

Post by AcelaExpress » 2021/08/23 20:59:48

It turns out I had an alias for ssh connections in my .bashrc:

Code: Select all

alias ssh='ssh -q -Y -o TCPKeepAlive=yes -o ServerAliveInterval=30'
If I remove the -Y flag (for trusted X11 forwarding) the problem goes away. Curious, I tried -X instead and the problem returns.

Probably not worth worrying about, but I found it curious the -Y and -X flags introduce a delay or prevent a passwordless ssh command from exiting cleanly.

Should this issue be reported since it was not a problem on Centos 7?

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