Date: Tue, 24 Jul 2007 20:00:05 -0400 From: Stephen Clark <Stephen.Clark@seclark.us> To: Alexey Karagodov <karagodov@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: pmtud + ipnat RELENG_6_2 appears to be broken Message-ID: <46A69285.1030801@seclark.us> In-Reply-To: <c7aff4ef0707241615u385f379bo36b07a3a788ea4b7@mail.gmail.com> References: <469624D1.20108@seclark.us> <4696823B.9020107@seclark.us> <AF67C2DA-4E77-48C5-B380-56D5D39043F4@mac.com> <46969129.60409@seclark.us> <3C09F7E4-C15A-4B9E-94A3-C4997C73C0BD@mac.com> <c7aff4ef0707241615u385f379bo36b07a3a788ea4b7@mail.gmail.com>
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Alexey Karagodov wrote: > is there any progress? > > just one "me too" > > this problem appeared for me when i try to use vlan over lagg ( to em > NICs ) > > thanx > kernel: vlan301: discard oversize frame (ether type 800 flags 3 len > 1514 > max 1510) > > > > 2007/7/13, Chuck Swiger <cswiger@mac.com <mailto:cswiger@mac.com>>: > > On Jul 12, 2007, at 1:38 PM, Stephen Clark wrote: > >> 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.... > > > > 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. > > Taking a quick look at ether_input() in src/sys/net/if_ethersubr.c > suggests that you are right-- if the incoming packet exceeds the MTU > being set, the input errors count for that interface is incremented, > but no ICMP_UNREACH_NEEDFRAG is generated even if DF flag is set. > > You might file a PR and see whether you can get Andre or one of the > other networking gurus interested in fixing this. Or maybe I'll give > it a try myself if I can get some free time.... :-) > > -- > -Chuck > > > _______________________________________________ > freebsd-stable@freebsd.org <mailto:freebsd-stable@freebsd.org> > mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to > "freebsd-stable-unsubscribe@freebsd.org <http://freebsd.org>" > > No progress - still being discussed on freebsd-net mailing list as: Re: 6.2 mtu now limits size of incomming packet 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)
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