Date: Thu, 12 Jul 2007 16:38:01 -0400 From: Stephen Clark <Stephen.Clark@seclark.us> To: Chuck Swiger <cswiger@mac.com> Cc: freebsd-stable@freebsd.org Subject: Re: pmtud + ipnat RELENG_6_2 appears to be broken Message-ID: <46969129.60409@seclark.us> In-Reply-To: <AF67C2DA-4E77-48C5-B380-56D5D39043F4@mac.com> References: <469624D1.20108@seclark.us> <4696823B.9020107@seclark.us> <AF67C2DA-4E77-48C5-B380-56D5D39043F4@mac.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Chuck Swiger wrote: >On Jul 12, 2007, at 12:34 PM, Stephen Clark wrote: > > >>Did something change in 6.2? If my mtu size on rl0 is 1280 it won't >>accept a larger incoming packet. >> >> > >Nothing changed; that is the expected behavior. >(Modulo support for 4-byte VLAN tags.) > > > >>kernel: rl0: discard oversize frame (ether type 800 flags 3 len >>1514 > max >>1294) >> >>I don't think it worked this way in the past. >> >> > >Well, it did. :-) > > > >>Won't this affect pmtud? >> >> > >Nope. > > > >>man page for ifconfig says mtu limits size of "transmission" not >>reception. >> >> "mtu n Set the maximum transmission unit of the interface to >>n, default >> is interface specific." >> >> > >The MTU is actually defined in reference to a network segment such as >an "ethernet collision domain", and applies to all machines sending >traffic to that segment. If the MTU is really 1280, nobody else >should be sending larger packets, and the drivers will drop any >larger packets they receive and generate the appropriate ICMP error.... > > > Hi Chuck, First thanks for responding but thats the problem, this did't generate an icmp when the packet was dropped. kernel: rl0: discard oversize frame (ether type 800 flags 3 len 1514 > max 1294) This message did not result in any icmp packet. I was running tcpdump looking for them. Steve -- "They that give up essential liberty to obtain temporary safety, deserve neither liberty nor safety." (Ben Franklin) "The course of history shows that as a government grows, liberty decreases." (Thomas Jefferson)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?46969129.60409>