topic Re: UCX Commands in Operating System - OpenVMS

UCX Commands

Mike D'Amico — Tue, 20 Jan 2009 21:11:04 GMT

Hello, I am using OpenVMS v7.2-1 on an Alpha 8200. I need to increase the number of TELNET sessions allowed from 400 to 514. I have used the command UCX> SET SERVICE TELENT/LIMIT=514. However, when I do a UCX> SHOW SERVICE TELENT/FULL the limit has not increased. Do I have to stop/restart TELENET services or reboot the server now? Also, will this change also affect the permanent DB?

Re: UCX Commands

Hoff — Tue, 20 Jan 2009 21:44:40 GMT

Yes, restart telnet. Or restart TCP/IP services. Or reboot.

Yes, it's permanent. (But it's not dynamic. See above.)

One of the existing discussions found via Google:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=960393

The limits dictated by the system parameters CHANNELCNT and IJOBLIM and a few other tweaks can also come into play here.

Re: UCX Commands

Andy Bustamante — Tue, 20 Jan 2009 21:47:27 GMT

You need to:

UCX DISABLE SERVICE TELNET
UCX ENABLE SERVICE TELNET

I recomend not doing this from a telnet session of course. The change is to the permanent configuration. Are you limiting logins? You can also use SET LOGIN /INTERACTIVE=514 as long as your telnet limit also allows these connections.

With 7.2-1 you can also move to TCPIP 5.1, which corrects some telnet connection issues with appropriate ECOs. Do doubt you're aware that 7.2-1 is years out of support.

Andy Bustamante

Re: UCX Commands

John Gillings — Tue, 20 Jan 2009 22:58:41 GMT

Mike,
Just in case it's not obvious...

$ TCPIP DISABLE SERVICE TELNET
$ TCPIP ENABLE SERVICE TELNET

will kill all existing TELNET sessions.

So, you've got 400 users connected using telnet, and you need some more. The only way to do it is to ask all 400 users to logout first? What is wrong with this picture?

The OpenVMS Ambassadors have been lobbying TCPIP Engineering for years to find a way to be able to increase telnet limits without requiring a DISABLE/ENABLE :-(

Maybe one day...

Re: UCX Commands

Hoff — Tue, 20 Jan 2009 23:11:02 GMT

IIRC, the TCP/IP engineering folks were quite fond of recommending use the shutdown and startup procedures - and not the DISABLE / ENABLE sequence - for some years. There were (at least in years past) cases where DISABLE / ENABLE would leave the system state in the weeds for certain of the server applications.

Re: UCX Commands

Wim Van den Wyngaert — Wed, 21 Jan 2009 07:14:26 GMT

May be there are a lot of dangling sessions from e.g. people that power off their pc when going home. Decreasing the keepalive time could decrease the number of such sessions and thus may be avoid the need to increase the parameter.

There are also scripts around that kill long-time idlle sessions (e.g. 24h without touching a key).

fwiw

Wim

Re: UCX Commands

Mike D'Amico — Wed, 21 Jan 2009 14:00:28 GMT

Rebooted server this AM. The change took. Thanks for your help. I will implement the keepalive timer as well. Great suggestion!!!

Re: UCX Commands

Mike D'Amico — Wed, 21 Jan 2009 14:11:21 GMT

Problem solved. Rebooted server and changes were applied. Also implemented the Keepalive timmer as suggested.