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how to set tcp_keepalives_kill

prakasse
Advisor

how to set tcp_keepalives_kill

Hi friends,

I am trying to set tcp_keepalives_kill value to 5000 from default value of 1 in HP-UX Integrity server[11.31]. I am getting this error message.

$ ndd -set /dev/tcp tcp_keepalives_kill 5000
operation failed, Invalid argument

$ uname -a
HP-UX test B.11.31 U ia64 3785580200 unlimited-user license.

Kindly let me know how to go about this.

Thanks,
Senthil.
Correct answer will get full 10 points
5 REPLIES
Turgay Cavdar
Honored Contributor

Re: how to set tcp_keepalives_kill

tcp_keepalives_kill aparameter is listed in unsupported parameters. tcp_keepalives_kill cannot be modified. It is set to 1.

#ndd -h unsupported | grep tcp_keepalives_kill
tcp_keepalives_kill - Types of keep-alive probe to use
Suraj K Sankari
Honored Contributor

Re: how to set tcp_keepalives_kill

Hi,

TCP_KEEPALIVES_KILL
Description: Determines the maximum number of times to probe before dropping.
How to view or set: Use the ndd command to determine the current value or to set the value. For example:

ndd -set /dev/tcp tcp_keepalives_kill 5000

Default value: 1
Recommended value: 5000 milliseconds

Suraj
Laurent Menase
Honored Contributor

Re: how to set tcp_keepalives_kill

Hi Prakasse,

help text is wrong
it is 0 or 1.

0 - we make a keepalive probe, so a simple ack is sent. If peer find it out of state it will sent a reset. Else nothing happens and connection persist.
1 - we make a keepalive kill, we resend the last sent byte, so if after tcp_ip_abort_interval and normal retransmission we don't get an ACK, then we kill the connection..

You should probably raise it to hp support.
Laurent Menase
Honored Contributor

Re: how to set tcp_keepalives_kill

the option to control the number of retransmission there are new setsockopt()
at TCP level TCP_KEEPINTVL and TCP_KEEPCNT
but be sure to be uptodate with xport patches.
man 7p tcp.
Laurent Menase
Honored Contributor

Re: how to set tcp_keepalives_kill

in fact tcp_keepalives_kill ndd param has no help text, so nothing to raise to hp support as it is an unsupported one.
- and in most case it should not be changed.

If you want to have more control about it, use setsockopt() at application level
ndd params beeing general to all of the applications.