Re: PROBLEM: networking - port 80 not accessible on eth0

Added netdev though this is unlikely to end up being dev related.

On Fri, 9 Jan 2009, Orgad Shaneh wrote:

---------- Forwarded message ----------
From: Orgad Shaneh <redacted>
Date: Fri, Jan 9, 2009 at 8:20 AM
Subject: PROBLEM: networking - port 80 not accessible on eth0
To: linux-kernel@vger.kernel.org


I have a "VIA Technologies, VIA Technologies, Inc. VT6102 [Rhine-II]"
NIC connected to an ECI B-FOCuS 270PR ADSL model. I used fedora since
version 5. On FC5 (using kernel 2.6.15) the modem functioned as a
router, and it worked fine.

When I upgraded to FC6 (which was published with kernel 2.6.18) I
couldn't access any websites. I found out that I can access https, ftp
etc. but not http. I figured out that for some reason, port 80 was
blocked. When using VMWare with Windows, I could access websites.

I configured the modem to be a bridge, and I'm connecting through
pppoe. This way it works. Anyway, although I can access websites on
ppp0, I cannot access the modem itself (for configuration), which is
on eth0 port 80.

I attached a tcpdump when trying to connect to the modem (the same
applies for websites, when the modem is configured as a gateway):

After trying some different distributions (fedora up to 9, ubuntu 8.04
and 8.10), the problem remains. That's what leads me to the conclusion
that the problem is in the kernel.

Unlikely so, more likely the router is broken and some kernel TCP settings 
got changed in the newer kernels. I took a short look into the provided 
tcpdump and the modem negotiates tcp connection ok but then goes dead 
silent.

Your could try playing around with tcp_window_scaling sysctl,
most likely the modem has some problem related to it.


-- 
 i.