openssh unix dev - Sep 2006 - openssh-4.3p2: setsockopt() problem

List,

I'm behind a dlink DSL-G604T wireless router.  ssh client was hanging at:

debug1: Entering interactive session.

Telnet was having a similar problem to port 22, however a simple client.c
I compiled was not.  My java ssh client was also working. After some
investigation, I noticed that the hang was after the system call:

setsockopt(3, SOL_IP, IP_TOS, [16], 4)  = 0

I noticed also that telnet was hanging the same way.  I commented all the
setsockopt() calls out of the ssh client code (because I was in a hurry)
and now it works.  Anyway, I figured I should document the problem
somewhere.

-Ken

_______________________________________________
openssh-unix-dev mailing list
openssh-unix-dev at mindrot.org
http://lists.mindrot.org/mailman/listinfo/openssh-unix-dev

List,

I'm behind a dlink DSL-G604T wireless router.  ssh client was hanging at:

debug1: Entering interactive session.

Telnet was having a similar problem to port 22, however a simple client.c
I compiled was not.  My java ssh client was also working. After some
investigation, I noticed that the hang was after the system call:

setsockopt(3, SOL_IP, IP_TOS, [16], 4)  = 0

I noticed also that telnet was hanging the same way.  I commented all the
setsockopt() calls out of the ssh client code (because I was in a hurry)
and now it works.  Anyway, I figured I should document the problem
somewhere.

-Ken

Hi,

On Sun, Sep 10, 2006 at 11:34:54PM -0700, Kenneth Berland
wrote:
> I'm behind a dlink DSL-G604T wireless router.  ssh client was hanging
at:
> 
> debug1: Entering interactive session.
This happens if you have a NAT implementation that cannot handle 
connections that change their ToS (Type of Service) flags "in flight".

I don't have a good idea how to work around those, though (well, when
I ran into this first time, I just tried using putty, which worked, 
because it doesn't modify the ToS bits).

gert

-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at
greenie.muc.de
fax: +49-89-35655025                        gert at
net.informatik.tu-muenchen.de
_______________________________________________
openssh-unix-dev mailing list
openssh-unix-dev at mindrot.org
http://lists.mindrot.org/mailman/listinfo/openssh-unix-dev

This is likely due to the router and how it is handling header 
information. If it's rewriting portions of the header after the syn is 
sent I could see a connections hanging.

Getting a tcpdump of a connection on both sides would probably let you 
figure out exactly where the badness is taking place.

Kenneth Berland wrote:
> List,
> 
> I'm behind a dlink DSL-G604T wireless router.  ssh client was hanging
at:
> 
> debug1: Entering interactive session.
> 
> Telnet was having a similar problem to port 22, however a simple client.c
> I compiled was not.  My java ssh client was also working. After some
> investigation, I noticed that the hang was after the system call:
> 
> setsockopt(3, SOL_IP, IP_TOS, [16], 4)  = 0
> 
> I noticed also that telnet was hanging the same way.  I commented all the
> setsockopt() calls out of the ssh client code (because I was in a hurry)
> and now it works.  Anyway, I figured I should document the problem
> somewhere.
> 
> -Ken
> 
> _______________________________________________
> openssh-unix-dev mailing list
> openssh-unix-dev at mindrot.org
> http://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
_______________________________________________
openssh-unix-dev mailing list
openssh-unix-dev at mindrot.org
http://lists.mindrot.org/mailman/listinfo/openssh-unix-dev