"Nicholas Lee" <nj.lee@plumtree.co.nz> wrote:
>I'm seeing something similar with my MW1122. ssh terminal sessions (ie.
>ssh -t volcano mutt) hang after a certain period of inactivity.

Sounds like the inactivity timer on the NAT is getting you -- don't know
about the specifics for the MW1122, but pretty much all NAT
implementations I've run across mop up NAT entries after a period of
inactivity; for TCP, this usually defaults to an hour.

There is such a thing as TCP keepalives, that most TCP stacks implement.
Unfortunately, these usually trigger at two hour intervals. I usually
set the TCP NAT timeout, if I can, to three hours -- that way, the
keepalives will keep the NAT entry for long term TCP sessions alive,
while still letting the NAT mop up stale entries.

If there isn't a way to control the TCP timeout (I can't find it in the
MW1122 manual. but I haven't looked very hard), or some of the TCP
stacks involved don't do TCP keepalives, you have to keep the channel
alive yourself.

If you're running a VPN, a periodic ping from an internal address to an
internal address at the other end of the VPN tunnel should keep the
thing alive.

For terminal sessions, this is a tad more difficult -- if your remote
system is a modern-ish Unix box, a little script along the lines of:

#! /bin/sh
#
# Little ditty to periodically put out a NUL character to keep the
# session alive
#
while printf '%c' '' # Send a NUL every ...
do sleep 300 # ... five minutes ...
done & # ... from the background.

should do the trick nicely.

-- don

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Received on Thu Jan 4 01:02:11 2001