tcp_keepalive_interval doesn't keep port 6000 alive

[Lisa Mauer]

I am using an X session to monitor unix servers through a firewall. I set the tcp_keepalive_interval which keeps all the telnet sessions active (otherwise inactive got disconnected after 1 hour - thanks to the internal firewall), anyway, does anyone know why port 6000 does not keep alive?? The firewall guys tell me they don't have anything coded for this port specifically so it has to be our server treating that port differently.... This is on HP 11i.
Thanks!
Lisa

[A. Clay Stephenson]

I am leaning heavily towards a firewall idle connection timeout. My first cut at this would be to monitor on the same side of the firewall. If it does not disconnect on the same side of the firewal but does going through the firewall then that has to be a firewall or router timeout.

[A. Clay Stephenson]

Thought number two: You don't really indicate what this X seesion does. Is it using tcp protocol? If not (e.g. udp) then the tcp_keepalive_interval would not apply.

[A. Clay Stephenson]

Sorry Lisa, I'm an idiot. I just remembered what port 6000 does - X11. I would still do the test on the same subnet to see if it's firewall.

[rick jones]

The tcp_keepalive_interval tuanble affects how soon keepalive probes are set - but only for those aplications that have explicitly enabled keepalives through a setsockopt() call with SO_KEEPALIVE as one of the parameters.

If the application driving port 6000 has not set SO_KEEPALIVE on its socket(s) then tcp_keepalive_interval will have no effect.

ftp://ftp.cup.hp.com/dist/networking/briefs/annotated_ndd.txt

And no, there is no way to enable keepalives on a system-wide basis. You need to get the application using port 6000 coded to set SO_KEEPALIVE.

[Lisa Mauer]

Thanks for the responses! The firewall guys again state that they do nothing different so it must be the application and what you say about it treating it differently. The only thing I use this for is GlancePlus gpm XSession to monitor my servers. I have checked the manuals and I do not see anything I can change to fix this - any ideas or am I just SOL?

[rick jones]

if you have a gpm going in this X session, make sure it is in a mode that it will continue to do updates to the display and things shoudl be OK.

i suppose you could also ask for an enhancement to the X libraries to include a setsockopt(SO_KEEPALIVE)

[Lisa Mauer]

Hi Rick:
I do have it set to update the GlancePLus - Process list and Main screens every 15 seconds, that doesn't seem to help at all, which surprises me..... It's as though the firewall is getting multiple connections or something and it closes one that isn't getting activity, which in turn just hoses everything up to a point that I have to reboot in order for it work come back....

[Massimo Bianchi]

Did you try to start an xclock in background with the nohup ? I used this and often worked.


nohup xclock &

gpm &

and after a good

top

to keep also the terminal alive.

HTH,
Massimo