Tcp problems (with solaris)

Pedro Roque Marques (
Mon, 13 May 1996 15:28:46 +0100

>>>>> "Giles" == Giles Douglas <> writes:

Giles> Ok, I'm not sure what exactly is causing this problem, but
Giles> its weird. Basically, I have a sun ultrasparc. No problems
Giles> with it until yesterday, when we moved a heavily-hit web
Giles> site on to it. Now if I telnet from linux (kernels 1.3.100,
Giles> 1.99.2, 1.3.91) to the sun, I get very slow, patchy
Giles> responses. (Best seen doing that great old test of holding
Giles> down a key for a long time.)

Giles> The odd bit is, if I start a connection to the sun via an
Giles> xterm I don't get the problem. Nor do I going from the sun

Can you strace the xterm to find out if it disables nagling via
setsockopt ?

Anyway connections to Solaris in link where speed is slightly
inferiour to ethernet speed are supposed to be slow if you don't
configure the retransmit times (ndd /dev/tcp retransmit_interval_* or
something in that lines).

Solaris 2.{4,5} has some very very broken TCP behaviour.
Do a tcpdump on the wire and you'll see the Solaris host retransmiting
like mad, sending double acks and having a completly insane behaviour.