On 26 September 2013 11:30, Keith Owens <kaos@ocs.com.au> wrote:
On 26/09/13 11:27, Toby Corkindale wrote:
On 26 September 2013 11:21, Keith Owens <kaos@ocs.com.au> wrote:
On 26/09/13 11:19, Toby Corkindale wrote:
Well, putting this iptables rule at the head of my FORWARD chain solves the problem: iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
I still have absolutely no idea why this worked fine on one router, and fails on another though!
That only works for TCP, you will probably still have problems with large UDP transfers. Indeed. I'd rather fix the root cause if it can be found.
Have you checked for large packets going between the server and the modem? That is, any packets > MTU. That is a sure sign of offload getting the way.
It's PPPoE, so the pppd runs on the server and sends ethernet (not IP) packets to the modem. This all used to work fine and nothing has changed on the server side.