topic Re: TCP/IP connect timeout on HP-UX 11.31 in Operating System - Linux

TCP/IP connect timeout on HP-UX 11.31

Ulrich Stammberger — Tue, 03 Feb 2009 13:48:00 GMT

Hello,

is there anyone who can tell me if it's possible to modify the tcp/ip connect timeout. The Default settings is 60s and i would like to change it to 10s.

I've checked some ndd tcp parameter, but i don't know if there is one to modify the timeout settings.

Udo

Re: TCP/IP connect timeout on HP-UX 11.31

Ganesan R — Tue, 03 Feb 2009 14:30:46 GMT

Hi,

By changing the TMOUT variable we can set the telnet sessions timeout. To see the currently set value
#echo $TMOUT
0
If it returns the value of 0 means it is indefinite. Sessions will not get disconnected at all.

If want the sessions to be disconnected if it is idle for 120 seconds set like this.

#export TMOUT=120

So if any sessions are idle for 120 seconds then the session will be disconnected. This is temprory only. If you want to set it permanently add the entry in /etc/profile or individual user profile(~HOME/.profile)

If TMOUT value is 0 and if still sessions gets disconnected, then there could be network settings. Need to contact network administrator. In the network, the network administrator may have set the settings in such a way that if any telnet connection is idle for more than a defined time then the session will be disconnected at router level..

Re: TCP/IP connect timeout on HP-UX 11.31

bright image — Tue, 03 Feb 2009 14:45:10 GMT

The following two commands will list all the ndd parameters for tcp/ip. Not sure which you will need to modify though.

ndd -get /dev/tcp ?
ndd -get /dev/ip ?

Re: TCP/IP connect timeout on HP-UX 11.31

rick jones — Wed, 04 Feb 2009 00:14:44 GMT

Assuming my 11.11-based knowledge is still current :)

You might look into tcp_ip_abort_cinterval - that is how long TCP will wait for an ACK of a SYN or SYN|ACK segment.

Keep in mind though that ndd settings are system-wide, and that the initial timeout will be based on tcp_rexmit_interval_initial and double each time. So, setting tcp_ip_abort_cinterval to 10 seconds may only give one or two retransmissions of the SYN or SYN|ACK segment.

For "supported" tunables, one can issue the command:

ndd -h

for a decent description.

Re: TCP/IP connect timeout on HP-UX 11.31

Sani — Wed, 04 Feb 2009 12:02:04 GMT

Hi

Check the following ndd parameters ,

tcp_time_wait_interval
tcp_tw_cleanup_interval

use ndd -h for help

Re: TCP/IP connect timeout on HP-UX 11.31

Ulrich Stammberger — Thu, 05 Feb 2009 10:34:18 GMT

Thank for your assistance,

i will test the ndd settings later.

Actually i have placed a workaround into my shell script.

Do a ping before i start a tcp/ip connection.

Thank you all

Udo

Re: TCP/IP connect timeout on HP-UX 11.31

rick jones — Thu, 05 Feb 2009 17:50:16 GMT

Pings - specifically ICMP Echo Requests and Reponses - may be blocked by firewalls which would otherwise let traffic pass. As such, a ping not working may be a false positive on an unreachable system.