[pptp-server] Wierd latencies

[Josh Howlett]

I have a poptop server running on Linux 2.4.10.  The VPN works fine,
which is good :-).  However, I am periodically getting very high
latencies over the VPN.  If I ping a host on the same subnet as the
poptop server, I find that the ping RTT values will stay constant at
10ms for a random number of pings, then suddently increase to about
800ms, sometimes peaking to 1000ms!  Then, after a random number of
pings it will suddenly change back to 10ms.

There usually aren't any intermediate values: it's either 10-12ms or
800-1000ms.

I've been testing this over a 100Mb/s network; the ping time between two
hosts on this network (without PPTP) is usually around 50us (not ms).
So, it looks like a software problem on the PPTP server.

Anyone got any ideas?

josh.

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Josh Howlett, Network Support Officer,
Networking & Digital Communications,
Information Systems & Computing,
University of Bristol, U.K.
0117 928 7850 | josh.howlett at bris.ac.uk
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