Subject: Networking oddities
To: None <>
From: George Coulouris <>
List: port-i386
Date: 11/01/1998 17:25:11
I've had RoadRunner cable modem service installed and working for about
a week. It works well for the most part, but I'm getting some strange
network behaviour I can't quite figure out.

First, the topology. There's porter (runs i386, has two ne2000's. ne1 to the
cable modem (Motorola cybersurfr wave), ne0 to the inside), lager (NT box),
and bock (ELC running netbsd/sparc). There's a coax segment that connects
the 3 machines.

I'm running the same ipnat config that I ran with dialup ppp, and that
works ok.

Next, some data points:

Web serving is fast (try it yourself, :-) )
Samba serving is fast.
Uploading by ftp is fast, I get 64 kbytes/s sustained.
Downloading by ftp is fast, I've gotten up to 180 kbytes/s.
ssh is fast. X over ssh is fast. scp is fast.

Now, the strange things:
telnet is slow.
nntp is slow.
web browsing is slow.

By slow, I mean the server will send some data, pause for 10-30 seconds,
send some more data.. Unusably slow. telnet feels like a bursty 1200 baud
modem, if that.

I don't think it's a routing or congestion problem. Traceroutes look fine,
and I get good speeds with ftp.

Any ideas ?

Also, an annoying subproblem: When I run dhclient ne1, it likes to clobber
ne0 and set its ip to I'm running the latest dhcp from isc. How to

Thanks in advance,

George Coulouris -