topic Re: where? TCP SO_KEEPALIVE and SO_RCVTIMEO in Operating System - HP-UX

where? TCP SO_KEEPALIVE and SO_RCVTIMEO

Todd McDaniel_1 — Fri, 07 Dec 2007 15:58:00 GMT

I am not familiar with these variables, can some one please advise me on where to find them on my hpux system?

TCP SO_KEEPALIVE and SO_RCVTIMEO

thanks.

Re: where? TCP SO_KEEPALIVE and SO_RCVTIMEO

James R. Ferguson — Fri, 07 Dec 2007 16:01:35 GMT

Hi Todd:

See the 'ndd' manpages.

Regards!

...JRF..

Re: where? TCP SO_KEEPALIVE and SO_RCVTIMEO

Todd McDaniel_1 — Fri, 07 Dec 2007 16:06:44 GMT

i cant find those variables in the tunables or when i try to run ndd -get

I have a client asking for this. I need a more direct answer please. I dont know what these parms are.

Re: where? TCP SO_KEEPALIVE and SO_RCVTIMEO

Todd McDaniel_1 — Fri, 07 Dec 2007 16:09:15 GMT

is this some thing that has to be configured? my /etc/rc.config.d/nddconf has no variables defined.

Are there default values?

Re: where? TCP SO_KEEPALIVE and SO_RCVTIMEO

James R. Ferguson — Fri, 07 Dec 2007 16:10:16 GMT

Hi Todd:

Actually, the values for a socket connection are specified by 'setsockopt()' when a socket is setup.

http://docs.hp.com/en/B2355-60105/getsockopt.2.html

...but are goverend by tunable kernel parameters:

http://docs.hp.com/en/B2355-60105/ndd.1M.html

Regards!

...JRF...

Re: where? TCP SO_KEEPALIVE and SO_RCVTIMEO

rick jones — Sat, 08 Dec 2007 01:52:38 GMT

While applications should be implementing their own "keepalive" mechanisms and not relying on the one in TCP, once an application has set SO_KEEPALIVE, the ndd settings tcp_keepalive_interval will be how soon it starts sending keepalive probes. They will be retransmitted as if they were data segments until tcp_ip_abort_interval milliseconds have elapsed since the first unanswered keepalive.

SO_RCVTIMEO may be present in some HP-UX include files, but it is never more than a noop. Any application relying on it will be sadly dissapointed and will need to use something along the lines of select(), poll() or /dev/poll instead.

So, to what ends were you planning on using SO_KEEPALIVE and SO_RCVTIMEO?