Date: Wed, 28 Aug 2002 12:33:17 -0700 From: Jeff Behl <jeff@expertcity.com> To: net@freebsd.org Cc: Julian Elischer <julian@elischer.org> Subject: Re: MTU not working? Message-ID: <3D6D257D.5080300@expertcity.com> References: <Pine.BSF.4.21.0208191618520.32737-100000@InterJet.elischer.org>
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Just an FYI, but I have opened a bug report on this: http://www.freebsd.org/cgi/query-pr.cgi?pr=42137 so hopefully someone with the know-how can come up with a fix. jeff Julian Elischer wrote: > > On Mon, 19 Aug 2002, Steve Francis wrote: > > >>Allow me to respond for Jeff (we work at same place, and have both been >>looking this issue) >> >>ICMP's being blocked are the most common explanation for this - but >>this is not the case here. >> >>tcpdump run on the server system shows the ICMP fragmention required - >>DF bit set messages being received, and - the irrefutable proof that it >>is not an ICMP filtering issue -the FreeBSD system DOES lower the MTU >>for that host's cloned route to the value specified in the ICMP (1420 >>in the snippet below). New packets are segmented to sizes <= the new >>MTU, but it continues resend the original packet over and over, in the >>original 1500 byte size. >> >>So I still say FreeBSD has broken pMTU-D code. >> >>This is reproducible at will, so we can collect whatever info anyone >>wants. >> >> > > > Yes > tcp needs to forget it ever sent that data, and refactor the entire > transmit window. > > I'd agree this is a bug if it's reproducible by others too. > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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