strange TCP behaviour

strange TCP behaviour

[Denys]

Dear All

I have application, thats accept redirected requests from squid (over iptables
... -j REDIRECT), getting ip over getsockopt/SO_ORIGINAL_DST and throwing data
in to the tunnel.

And i have strange behaviour, when i do
sysctl net.ipv4.tcp_frto=0

And i try any website with attachments (means a lot of data going to be sent
to redirect), i am getting after 3-10 seconds message "Read error: Connection
timed out". Thats a bit strange, possible it is related to application, but i
guess kernel must not give error to recv/read (i dont know what squid is
using). It is a bit difficult to reproduce the problem, but i can give a
remote access to PC where all things installed. But i have no idea, who of
TCP(?) maintainers can help me with this. I think there is no app problem,
tcpdump looks normal, there is no reset(and message will be different in case
of reset).


--
Denys Fedoryshchenko
Technical Manager
Virtual ISP S.A.L.

Re: strange TCP behaviour

[Denys]

I forgot to mention, latest tested kernel (for now)
2.6.21-rc5
It's just not easy to upgrade, is there any changes after rc5 related to that?

On Tue, 8 May 2007 12:49:36 +0300, Denys wrote
> Dear All
> 
> I have application, thats accept redirected requests from squid 
> (over iptables .... -j REDIRECT), getting ip over 
> getsockopt/SO_ORIGINAL_DST and throwing data in to the tunnel.
> 
> And i have strange behaviour, when i do
> sysctl net.ipv4.tcp_frto=0
> 
> And i try any website with attachments (means a lot of data going to 
> be sent to redirect), i am getting after 3-10 seconds message "Read 
> error: Connection timed out". Thats a bit strange, possible it is 
> related to application, but i guess kernel must not give error to 
> recv/read (i dont know what squid is using). It is a bit difficult 
> to reproduce the problem, but i can give a remote access to PC where 
> all things installed. But i have no idea, who of TCP(?) maintainers 
> can help me with this. I think there is no app problem, tcpdump 
> looks normal, there is no reset(and message will be different in 
> case of reset).
> 
> --
> Denys Fedoryshchenko
> Technical Manager
> Virtual ISP S.A.L.
> 
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--
Denys Fedoryshchenko
Technical Manager
Virtual ISP S.A.L.