Solved

Mysterious loss of telnet session connections

Posted on 2002-06-27
7
486 Views
Last Modified: 2013-12-27
Got Solaris 8 (with latest 8_Recommended patches) running on a Sun Blade 100.  Mysterious thing is that on this box only (there are a couple other nearly identical machines where I don't have this problem), I'm having a very hard time keeping idle telnet sessions open.  Once left unattended, the telnet session abruptly disconnects after somewhere between 10 minutes and 5 hours of idle time.  I haven't been able to pinpoint what causes the variance in time, but it definitely happens each time even though the actual timing is inconsistent.

The users in question have /bin/sh as their shell and no TIMEOUT or similar environment variable set.

Any suggestions as to why these sessions are being disconnected and how to trace back the cause of the disconnect?  Happens when directly connected to the machine via the local ethernet segment, remote connection via dialup and via VPN.
0
Comment
Question by:tphipps
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
  • 2
7 Comments
 
LVL 51

Expert Comment

by:ahoffmann
ID: 7113373
Solaris has a TCP-timeout for idle connections which is 2 hours, usually. Not shure if this applies to Solaris 8 too.
0
 
LVL 38

Accepted Solution

by:
yuzh earned 100 total points
ID: 7115487
Check the /etc/saf/zsmon/_pmtab file to see if timeout is set, you can delete the timeout entry (make a backup of the
file before you use vi to cahnge it.

Here' some infor about the file format:


/etc/saf/*/_pmtab:

  {svc_tag}:{flags}:{id}:reserved:reserved:reserved:
  {device_path}:{tty_flags}:{return_count}:{service_path}:{timeout_seconds}:
  {tty_def}:{streamio_modules}:{login_prompt}:{disabled_msg}:{term_type}:
  {softcar_yn}:# {comment}

/etc/saf/_smtab:

  {pm_tag}:{pm_type}:{flags}:{restart_count}:{monitor_path args} # comment

   
0
 

Author Comment

by:tphipps
ID: 7115829
Thanks for the suggesions yuzh.

My /etc/saf/zsmon/_pmpipe file only references the hardwired serial ports /dev/ttya and /dev/ttyb.  It doesn't reference any of the pseudo ttys created for telnet sessions.  I was under the assumption that entries in this file are only for physically connected devices.  Am I wrong?  Should I try to create entries for the pts/n devices?

Here's my contents of the file

# VERSION=1
ttya:u:root:reserved:reserved:reserved:/dev/term/a:I::/usr/bin/login::9600:ldter
m,ttcompat:ttya login\: ::tvi925:y:#
ttyb:u:root:reserved:reserved:reserved:/dev/term/b:I::/usr/bin/login::9600:ldter
m,ttcompat:ttyb login\: ::tvi925:y:#
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 38

Expert Comment

by:yuzh
ID: 7120877
It looks like the timeout is set in somewhere else on your system, please don't edit the /etc/saf/*/_pmtab. We'll try
to find the source of the configuration setting.

Have a look at your /etc/default/login file for the shell timeout, if you see
TIMEOUT=300  (or other value), comment it out, and then reboot your system, see how it goes.

 

0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 7121278
> .. then reboot your system,
This is UNIX, not M$. You don't need to reboot ;-)
0
 

Author Comment

by:tphipps
ID: 7121298
I think I've solved this.  It appears to be two different factors:

1) Whe connected to the machine (it's at home) from work, the dropped sessions can be blamed on a 600 second idle TCP timeout that our firewall seems to have in place for all outbound sessions.

2) When connected to the machine from home on the local segment, the dropped connections can most often be traced back to VPN connect/disconnects.  It seems that about 50% of the time I initiate a VPN (Cisco VPN client) connection, it drops existing TCP connections to local hosts.

Thanks all for the suggions. Giving points to yuzh given that I learned a lot about the /etc/saf* tree in the process!
0
 

Author Comment

by:tphipps
ID: 7121299
Thanks Yuzh... This wasn't the solution, but some good info.
0

Featured Post

Enroll in May's Course of the Month

May’s Course of the Month is now available! Experts Exchange’s Premium Members and Team Accounts have access to a complimentary course each month as part of their membership—an extra way to increase training and boost professional development.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
How to Change Interface on Cisco IOU 11 127
Image not there 4 74
How to Insert a File Using Text Editor 9 110
touch cat vi differences 7 33
In tuning file systems on the Solaris Operating System, changing some parameters of a file system usually destroys the data on it. For instance, changing the cache segment block size in the volume of a T3 requires that you delete the existing volu…
Why Shell Scripting? Shell scripting is a powerful method of accessing UNIX systems and it is very flexible. Shell scripts are required when we want to execute a sequence of commands in Unix flavored operating systems. “Shell” is the command line i…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…

732 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question