Re: another micro patch

Alan Cox (alan@lxorguk.ukuu.org.uk)
Sat, 20 Jan 1996 00:57:23 +0000 (GMT)


> Well, I thought so! So here is another Tiny Patch for TCP that will
> fix this particular problem. The problem was that on a low-latency
> network, the timeout could fall below 200ms, which is a bad thing if
> you happen to talk to a host with delayed acks...

Its basically a bug in BSD's TCP stack but that doesn't help and you
have to work around it because there are so many buggy systems out there.

> rlogin is still sluggish when logging into a Linux box but it doesn't
> seem to be Alpha specific. Haven't looked into what's going on.
> Alan, I suspect this is a known problem, can you point me to a place
> where this is discussed/explained.

Linux boxes generally do tcp wrapper and then direct DNS lookups. The linux
libc uses resolv+ which does its lookups in a slower more secure fashion as
well. If you put something like

echo "Hello starting"

at the top of your login script you should see the delay is all in startup
and not in the network layer.

Alan