-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hi folks,
On 09/13/2016 02:58 PM, Stuart Henderson wrote: > > See "MTU/MSS ISSUES" in pppoe(4). > indeed, its documented, but its also a little bit misleading. Reading the man page I had the first impression that modifying the mtu and max-mss are equally effective. Apparently they are not. AFAIU setting the max-mss affects TCP traffic only (e.g. HTTPS). It defines the maximum payload block size on sending and receiving(!) data via TCP. UDP and other protocols are not affected. Very important to know if you run IPsec or openvpn or other non-TCP protocols over the PPPoE tunnel. The mtu works on ethernet level, giving the maximum packet size to send(!) to the next hop without fragmentation, regardless if the higher level protocol is TCP, UDP, ESP or whatever. Point is, setting the MTU does not affect the data flow from the peer back to your site. AFAIU this made the difference in this case. Reducing the max-mss seems to be a workaround for some networking issue I cannot fix. My current configuration uses both baby jumbo frames (mtu = 1508 on re0 and mtu = 1500 on pppoe0) and "scrub (max-mss 1452)" for TCP traffic on pppoe0 (1500 bytes - 40 bytes TCP/IP header - 8 bytes PPPoE frame). Regards Harri -----BEGIN PGP SIGNATURE----- iQEcBAEBCAAGBQJX2XrzAAoJEAqeKp5m04HL6XcH/AsbZ4Cw0d/h3gwJGLYsk5/m XehdN7Sc6c8yHRksVCShC59V24NO89Xx+/SM+oVz6cXrszhDKw2K0wkBhMj3+aRV n6HUImpbkfnDE0TraxllcmDOljADLJut95LAetVkufiSIGsZVeofyx6JXdoW9xld hHVGR90b31a4FdO2PZE9gn2Cq1vMroTOdhXzjvqbIPGoiBz1ojaETJbTZTYtbfDp HeK0Sm1NMRtTZDO0IB/T+1G4CM/Ocmdtp6Pl1sIjsojJF5JKltt8J8D4gPFIS7dd dTk81hTVAXJuTb5oMWizRyq95+5ZarPbMThBtgHDYotIafc1ZpuHqrAvuQcYmRs= =QB+k -----END PGP SIGNATURE-----
