On Mon, Aug 06, 2012 at 12:54:48AM +0930, David Walker wrote: > Daniel Melameth <daniel () melameth ! com> wrote: > > When using pppoe(4), MSS can be a problem. I recommend you read the > > MTU/MSS ISSUES section of the man page and see if that resolves your > > issue. > > I have read and tried. > As far as I can see there's an issue with incoming packets. > AFAIUI, MSS will limit the size of outgoing. > I'd like to know the relationship between that and path MTU and what I > see as the apparent default block on ICMP in pf ... > Sending packets is one thing but if a distant host is unable to > determine the MTU for the next hop (to me) via ICMP then there's a > problem right? > Does setting MSS on PPP and therefore MTU affect this? > Do I need to explicitly allow ICMP to enable this behaviour? >
The MSS field from your syn packages tells the other side what max package size you accept. I found this white paper helpful to understand MTU, PMTUD and MSS: http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800d6979.shtml Remi
