Hey, Are you dropping the fragmented pks on the end dst?
What mtu value are you using on your egress inet interface and LAN interface? Remember that gre has 24byte overhead so your LAN side needs to always be $x - 24 so if using 1508 on ur .inet facing interface then your LAN facing max mtu value should be 1484 else when client/server calculate mss they use the interface mtu as the mss value and add DF bit 1 on the frame since both sides don't see problems with 1500 size mss *default value* (while your internet/GRE side if the interface must fragment the packets due to oversized frames) That's why most times you get fragmented packets that don't reassemble at the dst side or simply get dropped on the path where the link does not support DF bit set to 1 (per interface option) Another solution is to simply increase mtu size on the ptp GRE links/path (if its a direct connection or you control your own backbone) to 1524 and avoid server/client mtu modifications Hope this helps... And if not, sorry for the ramble :) On 4/15/11, Leigh Porter <[email protected]> wrote: > Hello Rafal, > > Its been a while since you posted this! Did you ever manage the 1500B > MTU with this? > > I have some SRX boxes that correctly fragment the outgoing GRE packets > but the other Juniper does not reassamble them. > > Thanks, > Leigh > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Rafal > Grzeskowiak > Sent: 09 June 2010 13:19 > To: [email protected] > Subject: [j-nsp] MTU on pseudowire over GRE > > Hi! > > Is that possible to have MTU=1500B on any kind of pseudowire > configured over GRE tunnel between 2 J-series routers? > The tunnel is established over the internet, with access links' > MTU=1500B on both sides. I tried with CCC, l2circuit, l2vpn and various > settings of fragmentation, but I can't reach 1500B. > > Rafal > > -- > regards, > Rafal Grzeskowiak > > _______________________________________________ > juniper-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/juniper-nsp > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please visit http://www.messagelabs.com/email > ______________________________________________________________________ > > _______________________________________________ > juniper-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/juniper-nsp > -- Sent from my mobile device Payam Tarverdyan Chychi Network Security Specialist / Network Engineer _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
