On Tuesday 21 Feb 2012 22:19:19 Etienne Champetier wrote: > > A plausible example: > First default route: optical fiber (MTU 1500) > Second default route: pppoe (MTU 1492) (failover link) > If the optical fiber goes down, the traffic from the router will pass > through the PPPoE link, but with a MSS set to 1500-40 instead of 1492-40 >
Presuming, for a moment that you are multihomed and actually have the same IP usable on either interface (because, if you don't, your problem isn't the MSS) the correct solution is for the router to drop the oversized packet and send back an ICMP Fragmentation Needed/ICMPv6 Packet Too Big to the original sender who will then reduce the transfer size and sliding window accordingly. TCPMSS is ONLY ever needed for cases where someone criminally braindead is filtering the ICMP mentioned above, as I believe the manpage states. _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
