Hung connection over Juniper Tunnel

[Damien Miller]

On Fri, 6 Feb 2009, Jason Benguerel wrote:

> I have disabled TCP Window scaling on both the client and server. I  
> also confirmed that there are no MTU issues using ping (with the no  
> fragment flag and full payload.) There are reports of Juniper  
> firewalls causing similar issues, but I have applied the supposed  
> workaround of disabling TCP sequence checking (which they claim stops  
> the window scaling issue) and still have no results.
> 
> The sshd server is still replying with:
> 
> debug1: server_input_channel_open: ctype session rchan 0 win 1048576  
> max 16384
> 
> Which looks to me as if it is still trying to set a variable TCP  
> window despite turning the feature off via:
> 
> echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
> 
> Is there some other way to disable this in ssh/sshd?

No, the "win" here is the SSH session level windows which has little to
do with the TCP window. Stock OpenSSH doesn't touch the TCP window in
any way.

-d