From owner-freebsd-hackers Mon Sep 17 14:47:58 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by hub.freebsd.org (Postfix) with ESMTP id B86F737B40B for ; Mon, 17 Sep 2001 14:47:55 -0700 (PDT) Received: (from dan@localhost) by dan.emsphone.com (8.11.4/8.11.4) id f8HLlrI06320; Mon, 17 Sep 2001 16:47:53 -0500 (CDT) (envelope-from dan) Date: Mon, 17 Sep 2001 16:47:42 -0500 From: Dan Nelson To: David Preece Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Fwd: MTU table? Message-ID: <20010917164742.A13516@dan.emsphone.com> References: <01091809402216.83234@development.wgtn.csg.co.nz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <01091809402216.83234@development.wgtn.csg.co.nz> User-Agent: Mutt/1.3.22.1i X-OS: FreeBSD 5.0-CURRENT X-message-flag: Outlook Error Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In the last episode (Sep 18), David Preece said: > I tried this on -questions but to no avail. It strikes me as something that > is either dead easy, or can't be done. Does anyone have any ideas? If "route get " shows an MTU of 576, "route delete " should clear it. > I have a network consisting of: > > Server (mtu1500)<->(mtu1500)gateway(mtu576)<->Client (mtu1500) > > The server and gateway are both FreeBSD4.x machines and the client is > NT4, hence changing MTU is a bit of a mystery, but I digress. So, the > first time the client connects to the server and the server attempts > to send back a packet of over 576 bytes, the gateway objects and > sends back an ICMP 3(4) saying that the packet can't be forwarded > until the MTU is reduced to 576. The server tries again with the new > MTU and all is well. > > The kernel on the server also has the good sense to remember that > there's an MTU of 576 bytes on that route and doesn't try anything > larger in future. This would be great *except* that I'm trying to > turn the whole thing into a factory for ICMP cannot fragment > messages. Is there a simple way to flush the route->mtu table on the > server? -- Dan Nelson dnelson@allantgroup.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message