Dear Pavel, Have you tried adjusting MSS on the tunnel interface:
e.g. ip tcp adjust-mss 1400 Also search [www.cisco.com] for PMTUD (watch the line wrap): http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800d6979.shtml Best regards, -nick/ Pavel Gulchouck wrote: > Hi, > > On Thu, Sep 20, 2007 at 10:55:08AM +0100, Phil Mayers writes: > [...] > PM> So, ideally set your physical interface ip mtu to 1536, physical mtu to > PM> whatever IP overhead you have (e.g. 14 bytes on ethernet - 1550). > > I set mtu on physical interface and on SVI to 4096, set > "ip mtu 1500" on gre tunnel but with no luck: MTU on tunnel > interface is 1514, and if I try to increase it router responses: > "% Interface Tunnel2 does not support adjustable maximum datagram size". > Ping between tunnel source and tunnel dest with size 4096 and df > is ok, but all 1500-bytes packets are fragmented while encapsulating > into the gre tunnel. > 6500/sup720. > In addition I use ipsec (with SPA-IPSEC-2G), but MTU is unchangable > for unprotected gre tunnels too. MTU on virtual GE to ipsec module > is 9216. > Big unfragmented packets from remote router (7200) are successfully > receiving and decrypting. > > Any suggestions? > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
