Re: [B.A.T.M.A.N.] MTU/connection problem

[Michael Rack <michael.rack@rsm-freilassing.de>]

  I've read the complete topic, but dont't know if your problem is solved.

You're right. The MTU is your Problem. And when i read your post, it was 
clear for me, that your problems results on your VPN Connection.

You need to do some MSS stuff on your OpenWRT Router.

/sbin/iptables -t mangle -A forward -i tap0 -p tcp -m tcp --tcp-flags 
SYN,RST SYN -m tcpmss --mss 1381:65535 -j TCPMSS --set-mss 1460
/sbin/iptables -t mangle -A forward -o tap0 -p tcp -m tcp --tcp-flags 
SYN,RST SYN -m tcpmss --mss 1381:65535 -j TCPMSS --set-mss 1460

And all your problems are gone :-D

Liebe Grüße aus Freilassing,

Michael Rack
RSM Freilassing
-- 
RSM Freilassing                 Tel.: +49 8654 607110
Nocksteinstr. 13                Fax.: +49 8654 670438
D-83395 Freilassing            www.rsm-freilassing.de


Am 17.06.2010 10:18, schrieb Clemens John:
> Hi,
>
> I have a problem to connect to the Internet. We are using Batman advanced
> 0.2.1 and IPv4 here in oldenburg. Our setup looks like this:
>
> Laptop-[wifi]->Fonera-[wifi]->Dir300-->OpenVPN-->
> virtual OpenWrt machine-->internet.
>
> The default route of the laptop goes to the virtual OpenWrt machine wich
> provides an Internet connection.
>
> I can acces google (wget google.de) but not heise.de or golem.de. I´m not
> verry familar with network configurations but I heared that this might be an
> mtu problem.
>
> All devices in the network (tap0, ath0, ath1, wifi0) have an mtu of 1524 except
> bat0 and br-mesh which have an mtu of 1500.
>
> Our routers are configured to bridge connections from non batman devices (like
> the laptop) to bat0. This is done in the device "br-mesh".
>
> Everythink works fine, except I can´t connect to internet websites that are not
> google.de.
>
> When I decrease the mtu of the wireless device of the laptop to 1476
> everything works fine.
> But I have to do this by hand and on a client this is bad.
>
> Does anybody know what I´m doing wrong?
>
> Greetings
> Clemens