topic Re: SSH timeuot? in Operating System - HP-UX

SSH timeuot?

boje — Fri, 12 Sep 2008 07:05:55 GMT

Hi!

I have a machine that disconnects the cilent if it´s inactive for some minutes. This is not tha case on any of our other servers. I think this server is configured to be more secure than the others, but i can not find any difference in the config files. This is the file i have checked: /opt/sshd/etc/sshd_config Is there any other way to config the sshd service? With any other files? How do i know which config files are used on this system?

Br
Patrik

Re: SSH timeuot?

RAC_1 — Fri, 12 Sep 2008 07:11:48 GMT

On the basis of which ssh version and flavor you are using config files will vary!! Also if firewall is in between that can also terminate idle connection on the basis of how it's configured.

openssh seems to have this option-LoginGraceTime for timeouts. it's configured insshd_config. man sshd_config for details.

Also you can check if timeout happens for telnet or not or only for ssh. also check TMOUT variable.

Re: SSH timeuot?

boje — Fri, 12 Sep 2008 07:22:42 GMT

Hi!
ps -ef|grep sshd
root 823 1 0 Jun 29 ? 10:13 /opt/ssh/sbin/sshd
root 5232 4415 1 10:21:50 pts/0 0:00 grep sshd
root 4376 823 0 10:18:14 ? 0:00 sshd: root@pts/0

So it should be /opt/ssh/etc/sshd_config file that is used? Almost all lines in this file starts with #, it is not used?

Br
Patrik

Re: SSH timeuot?

Ivan Krastev — Fri, 12 Sep 2008 07:27:53 GMT

Check for TCPKeepAlive in sshd_config:

TCPKeepAlive

Use this directive to control the flow of TCP keep-alive messages. If keep-alive messages are sent, the connection terminates, or one of the hosts crashes, this directive prevents infinitely hanging sessions.

However, if keep-alive messages are not sent, sessions can hang indefinitely on the server, resulting in ghost users and large consumption of server resources.

The default setting is YES.

For example:

TCPKeepAlive YES

http://docs.hp.com/en/5991-7493/apas02.html

regards,
ivan

Re: SSH timeuot?

Sandeep_Chaudhary — Fri, 12 Sep 2008 08:21:13 GMT

set TMOUT=0 in .profile

it wont time out ur ssh session.

TCPkeepalive yes is another option in sshd_config

Re: SSH timeuot?

Ralph Grothe — Fri, 12 Sep 2008 08:59:03 GMT

> So it should be /opt/ssh/etc/sshd_config file that is used? Almost all lines in this file >starts with #, it is not used?

You can try this

$ $(UNIX95= ps -C sshd -o ppid= -o args=|awk '$1==1{print$2}') -h 2>&1|grep -- -f
-f file Configuration file (default /opt/ssh/etc/sshd_config)

Re: SSH timeuot?

boje — Fri, 12 Sep 2008 09:15:53 GMT

Hi!

When i compare these two systems, i can not find any differences in the config files. I do not know why the other system keeps timing out. This is from config file:

#TCPKeepAlive yes
#ClientAliveInterval 0
#ClientAliveCountMax 3
#MaxStartups 10

and i can not find any TMOUT= in .profile.

These settings are the same on both systems.

Br
Patrik

Re: SSH timeuot?

Sandeep_Chaudhary — Fri, 12 Sep 2008 09:51:12 GMT

u wont find TMOUT in .profile.
u can manually write

export TMOUNT=0

It works.