Date: Mon, 19 Aug 2002 16:20:37 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: Steve Francis <sfrancis@expertcity.com> Cc: Jesper Skriver <jesper@FreeBSD.org>, Jeff Behl <jeff@expertcity.com>, net@freebsd.org Subject: Re: MTU not working? Message-ID: <Pine.BSF.4.21.0208191618520.32737-100000@InterJet.elischer.org> In-Reply-To: <3D617842.4020304@expertcity.com>
next in thread | previous in thread | raw e-mail | index | archive | help
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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.4.21.0208191618520.32737-100000>