topic Re: Changing TCPIP-parameter in Operating System - OpenVMS

Changing TCPIP-parameter

Kirsten Knüttel — Wed, 22 Nov 2006 08:19:32 GMT

Hi,

on OpenVMS 7.3-1 with TCP/IP 5.3 Eco2 I can see many tcpip parameters:
TCPIP>sysconfig -q inet

how can I change these parameters (e.g. tcp_keepidle, tcp_keepcnt, tcp_keepinit) processwide (not systemwide)?

Regards,

Kirsten

Re: Changing TCPIP-parameter

Volker Halle — Wed, 22 Nov 2006 08:27:41 GMT

Kirsten,

these are TCPIP kernel parameters and apply to the TCPIP software systemwide. You can't set these parameters per process.

What are you up to ?

Volker.

Re: Changing TCPIP-parameter

Kirsten Knüttel — Wed, 22 Nov 2006 08:31:28 GMT

Hi,

a collegue just wants to test something with tcpip. So, when I must set them systemwide, just for interest, how can I set them.
is it wiht sysconfig -r ?

Regards,

Kirsten

Re: Changing TCPIP-parameter

Volker Halle — Wed, 22 Nov 2006 08:41:29 GMT

Kirsten,

yes, use TCPIP> sysconfig -r param=new_value

See $ TCPIP HELP SYSCONFIG

Volker.

Re: Changing TCPIP-parameter

Karl Rohwedder — Wed, 22 Nov 2006 08:41:34 GMT

sysconfig -r is the right tool.

ergards Kalle

Re: Changing TCPIP-parameter

Kirsten Knüttel — Wed, 22 Nov 2006 08:46:01 GMT

Hi,

first thank you all for your fast reply. Now my collegue has the following problem. He needs a tcpip-socket with an other idletime than the systemwide idletime. Is this possible?

Regards,

Kirsten

Re: Changing TCPIP-parameter

Wim Van den Wyngaert — Wed, 22 Nov 2006 08:48:49 GMT

sysconfig -r will modify the volatile settings.

I simply add the settings to tcpip$etc:sysconfigtab.dat and restart tcpip.

Wim

Re: Changing TCPIP-parameter

Kirsten Knüttel — Wed, 22 Nov 2006 08:51:20 GMT

Hi,

I can't restart TCPIP, it is a production system. But when I change them with sysconfig -r it is systemwide and this is, what I don't want.

Kirsten

Re: Changing TCPIP-parameter

Volker Halle — Wed, 22 Nov 2006 09:00:11 GMT

Kirsten,

if you want to set these options for a specific socket, you will have to do some programming !

See the description of the setsockopt() function call in the TCPIP Sockets API and System Services Programming manual:

http://h71000.www7.hp.com/doc/82final/6529/6529pro.html

Volker.

Re: Changing TCPIP-parameter

Kirsten Knüttel — Thu, 23 Nov 2006 03:51:07 GMT

Hi Volker,

I've discussed it with my collegue who needs the solution.
He said, that the API uses the parameter tcp_keepidle and can't be changed.
And here is a short description of his problem. On our VMS machine the socket is in server mode. The clients are mostly windows clients, SPS. Sometimes it happens that somebody cuts a network cable. Now the VMS server waits the tcp_keepidle time until he recognizes that the connection is not longer existing. The problem is, that the tcp_keepidle time on our machines is 2,5 h (not the default 75 seconds) and we can't change it. It would be now great if some processes who don't need this long time can have a shorter time for the timeout.

I hope I could it explain quite good.

Regards,

Kirsten

Re: Changing TCPIP-parameter

Volker Halle — Thu, 23 Nov 2006 04:40:52 GMT

Kirsten,

if I understand your description correctly, tcpip_keepidle is set to 2.5 hours on your system and you want this one application to use a value of 75 seconds. And you can't change that parameter in the setsockopt() call in the application.

If the tcp_keepidle value is hard-coded in the application and can't be changed at that level, I don't think you can expect TCPIP to be able to change this value 'behind the back of the process' for a given process/socket.

Volker.

Re: Changing TCPIP-parameter

Kirsten Knüttel — Thu, 23 Nov 2006 05:01:34 GMT

Volker,

it is not hardcoded in the application. In the documentation we found for the API that it uses the value of tcp_keepidle.
in TCPIP>SYSCONFIG.... the value for tcp_keepidle is 14400. this value is too long for this application.
I hope, I wrote it now in a better way. If it is still unclear I think it is better (sorry for the rest) to write it in german, or not?

Regards,

Kirsten

Re: Changing TCPIP-parameter

Volker Halle — Thu, 23 Nov 2006 06:15:27 GMT

Kirsten,

so the application seems to use the system-wide value for tcp_keepidle. And this value is set to 14400 and this is too long for this application. And you can't change that system-wide value due to other applications on that system requiring this large value.

If your application does not allow you to change the parameters of it's setsockopt() call, I see no way how you could change tcp_keepidle for that applications socket and have the rest of your other applications still use the larger value.

Volker.

Re: Changing TCPIP-parameter

Kirsten Knüttel — Thu, 23 Nov 2006 06:36:34 GMT

Volker,

Thank you very much