Keep alive settings for tcp/ip

[Paul Bishop]

How often are keep alive packets sent on a tcp/ip connection on an AIX system or is there a way to check what it is set to?  We are having an issue with one of our vendors with the connection being reset on their side and messages are then hung up until the cloverleaf thread is cycled.

Thanks!

Paul Bishop

Carle Physicians Group

Urbana, IL

Paul Bishop
Carle Foundation Hospital
Urbana, IL

Topic

[Rob Abbott]

On AIX the default interval is 75 seconds.

The command you want is “no” (network options).  “no -a” will show all the network settings.  “man no” for details.  Here’s the section on tcp_keepintvl:

Quote:

% no -h tcp_keepintvl

Help for tunable tcp_keepintvl:

Purpose:

Specifies the interval, measured in half seconds, between packets sent to validate the connection.

Values:

       Default: 150

       Range: 1 – 32767

       Type: Connect

       Unit: halfsecond

Tuning:

For example, 150 half seconds results in 75 seconds between validation probes. This will allow TCP to know that a connection is still valid and keep the connection open when it is otherwise idle. This is a configuration decision with minimal performance consequences. No change is recommended. If the interval were shortened significantly, processing and bandwidth costs might become significant.

.

Rob Abbott
Cloverleaf Emeritus

[Paul Bishop]

Thanks Rob!

I checked and we’re at the default (150).  another case of blame cloverleaf until we can prove them wrong.

Paul Bishop
Carle Foundation Hospital
Urbana, IL

[Michael Hertel]

What’s the difference between that and tcp_keepidle ?

https://usspvlclovertch2.infor.com/viewtopic.php?t=734

Quote:

On AIX —

The default keepalive setting for AIX is 2 hours. We have a lot of remote connections and had smilar issues until I lowered it to 15 mins. Now we never have that problem (although remote connections go down for other reasons, obviously, so they aren’t hassle-free). The keepalive setting affects all of the cloverleaf sockets.

To determine current keepalive setting:

$ no -a | grep tcp_keepidle

           tcp_keepidle = 14400  (14400=2 hours in 1/2-second intervals)

To change keep alive setting to 30 minutes (value is in half-second intervals):

– Login as Root and type the following command:

no -o tcp_keepidle=3600

(1800 for 15 minutes)

Also, add the command to the bottom of /etc/rc.net to auto-reset after reboot.

[Author]

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