topic Re: Possible TELNETD Issue in Operating System - HP-UX

Possible TELNETD Issue

Tom Whalen_1 — Tue, 30 Nov 2004 16:13:25 GMT

We have a application that is using a proprietary client using telnet as the underlaying communication layer. While using the client, the session will randomly time out which gives the perception to the users that the application has hung. Upon taking a packet trace, there seems to be a break in the IP traffic transmission thus dropping certain application-driven escape sequences which is used to paint a psuedo-GUI screen. The application vendor is pointing the figures to the HP server (big surprise there). But what's odd is they are referencing 2 patches that are suppose to clear this up and report it's a known bug in TELNETD but ITRC has not knowledge of the 2 patches. They are:

PHNE_29095 and PHNE_30695

The claim the HP is planning to release the patch under the 2nd patch ID in early 2005 but I'm not sure I believe it. Anyone else hear of these patches or seen this type of behaviour with TELNETD?

Thanks..
Tom - UNIX Sys Admin

Re: Possible TELNETD Issue

Paul Haygarth — Tue, 30 Nov 2004 16:26:56 GMT

Are the users, by chance, connecting into the Network via VPN?

I've had a few customers experience the same problem, when their users were running a telnet client over a VPN tunnel, and it turned out to be a TIMEOUT setting in the VPN Appliance or router.

Re: Possible TELNETD Issue

Tom Whalen_1 — Tue, 30 Nov 2004 16:30:34 GMT

Unfortunately they are local LAN connections. Interestingly enough, we called the response center to get more info on the above patches and they couldnt get any details on the 2 patch codes so they are checking with the HP Lab.

Thanks for the response..

Tom

Re: Possible TELNETD Issue

A. Clay Stephenson — Tue, 30 Nov 2004 16:39:33 GMT

I was going to suggest that you put in a support call; you might get a site specific patch that way -- if it exists.

I would play with the -z and -s telnetd options (especially the -z) in your /etc/inetd.conf line and see if that improves your behavior. Man telnetd for details.

Re: Possible TELNETD Issue

Scot Bean — Tue, 30 Nov 2004 16:39:57 GMT

It looks to me that the vendor may be correct. I found a reference to PHNE_29095, the patch DOES exist but is not publicly available. It is "site-specific" or "beta". You should be able to get a copy for your use thru your HP rep.

Re: Possible TELNETD Issue

Paul Haygarth — Tue, 30 Nov 2004 16:48:24 GMT

I just thought of something else. After we upgraded to HP-UX 11i, we did notice that users would have pauses during screen refreshes in our application.

This was due to many small packets being transmitted back and forth between the terminal emulation and the application.

It could be that the Application your are running is doing the same thing. You can force telnetd, to wait and transmit larger packets by changing the /etc/inetd.conf to use the -TCP_DELAY option, which worked for us.

So the line in inetd.conf will look like this:

telnet stream tcp nowait root /usr/lbin/telnetd telnetd -TCP_DELAY

Then force a reread of inetd.conf file by running 'inetd -c'.

Re: Possible TELNETD Issue

Tom Whalen_1 — Tue, 30 Nov 2004 16:48:29 GMT

Thanks - where did you find info on the patch? I'd like to review the patch spec and see what it addresses specifically.

Thanks!
Tom

Re: Possible TELNETD Issue

Scot Bean — Tue, 30 Nov 2004 17:18:55 GMT

The web source was internal to HP. I could not find an external one, except via your HP rep.

Re: Possible TELNETD Issue

Tom Whalen_1 — Tue, 30 Nov 2004 17:30:25 GMT

Would it be possible to email me the specs on the patch so I can follow-up with HP on this?

Thanks..
Tom