Mail attachment problem with IP TUNNELING

[mrmozaffari]

Hi

We are an Isp and we have two links separatly from two different service provider, one is for Send traffic and another one for recive traffic, we use simple Gre tunnle and configure it in our router ,the tunnel is active and everything seems works fine ,but when users want to use mail attachment like yahoo mail attachment they have problem : yahoo ask them to attach files they can browse and choose files after that when they want to finish ,the yahoo attachment page process opened and never finish it s job !!!!!!!

please help.

Thanks.

Reards Bahman mozaffari

[mheusinger]

Hi,

this sounds like you are having MTU problems due to the GRE overhead. You can try to fix this with the command

ip tcp adjust-mss ! f.e. 1400

on the tunnel interfaces. The riouter will intercept TCP MSS negotiation and allow only TCP segments small enough to fit through the tunnel.

Hope this helps! Please rate all posts.

Regards, Martin