server don't accept ip-connections from linux

server don't accept ip-connections from linux

[Dieter Ferdinand]

hello,
i have a big problem: some servers send a rst-packet or don't answer if i 
want to open a connection with them.

this happens with the web-server with ip 15.200.6.123 and my smc-
barricade router/printserver.

if i make a connection from windows or linux with kernel 2.2, it works, with 
kernel 2.4, i get a rst or no answer and the connection is closed.

i don't know, what is the difference of the tcp-packets from windows/kernel 
2.2 and linux with kernel 2.4. but with kernel 2.4 i have trouble with some 
servers.

i check the packets with an analyser and make some test. if i disable ecn 
with "echo 0x0 > /proc/sys/net/ipv4/tcp_ecn" it works, with ecn enabled, it 
don't work.

goodby

Schau auch einmal auf meine Homepage (http://go.to/dieter-ferdinand).
Dort findest du Information zu Linux, Novell, Win95, WinNT, ...

Re: server don't accept ip-connections from linux

[Bernd Eckenfels]

In article <457FD55E.13765.202391D@dieter.ferdinand.gmx.de> you wrote:
> i check the packets with an analyser and make some test. if i disable ecn 
> with "echo 0x0 > /proc/sys/net/ipv4/tcp_ecn" it works, with ecn enabled, it 
> don't work.

this is a problem on the remote site (old firewall software), nothing we
(linux kernel) can do about it. You might want to inform the owner of the
server about that.

Gruss
Bernd

Re: server don't accept ip-connections from linux

[Pete Harlan]

On Wed, Dec 13, 2006 at 10:26:38AM +0000, Dieter Ferdinand wrote:
> i don't know, what is the difference of the tcp-packets from windows/kernel 
> 2.2 and linux with kernel 2.4. but with kernel 2.4 i have trouble with some 
> servers.
> 
> i check the packets with an analyser and make some test. if i disable ecn 
> with "echo 0x0 > /proc/sys/net/ipv4/tcp_ecn" it works, with ecn enabled, it 
> don't work.

With kernel 2.6.17.13 or higher, you can limit the scaling factor for
that broken host with:

	THEIR_IP=1.2.3.4
	MY_GATEWAY=5.6.7.8

	ip route add $THEIR_IP/32 via $MY_GATEWAY window 65535

which limits window scaling for that destination without interfering
with your other connections.

--Pete