From owner-freebsd-net Sat Jan 4 3:39: 4 2003 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CF8D037B401 for ; Sat, 4 Jan 2003 03:39:02 -0800 (PST) Received: from shell.dragondata.com (shell.dragondata.com [66.250.147.249]) by mx1.FreeBSD.org (Postfix) with ESMTP id 14F2043EB2 for ; Sat, 4 Jan 2003 03:39:02 -0800 (PST) (envelope-from toasty@shell.dragondata.com) Received: (from root@localhost) by shell.dragondata.com (8.11.4/8.11.3) id h04Bd0782966; Sat, 4 Jan 2003 05:39:00 -0600 (CST) (envelope-from toasty) From: Kevin Day Received: (from toasty@localhost) by shell.dragondata.com (8.11.4/8.11.3av) id h04Bcwe82722; Sat, 4 Jan 2003 05:38:58 -0600 (CST) (envelope-from toasty) Message-Id: <200301041138.h04Bcwe82722@shell.dragondata.com> Subject: Traceroute through specific gateway/interface To: freebsd-net@freebsd.org Date: Sat, 4 Jan 2003 05:38:58 -0600 (CST) X-Mailer: ELM [version 2.5 PL5] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: by dragondata.com virus scanner Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Has anyone ever created a patch for traceroute that lets you force it to go through a specific interface, or use a certain gateway even if the routing table says otherwise? I know I can use source routing, but a good percentage of the routers on the internet drop source routed packets now. Here's my situation... I have a FreeBSD system running as a router to multi-home us between three uplinks, with us running Zebra for BGP. It'd be nice to occasionally take a look at a traceroute through one of the other uplinks. (other than the one that Zebra has added a route for) +-----------------------+ | | ISP-A | bge0 10.1.0.2/30 +----------> 10.1.0.1 | | | | ISP-B | bge1 10.2.0.2/30 +----------> 10.2.0.1 | | | | ISP-C | bge2 10.3.0.2/30 +----------> 10.3.0.1 | | LAN | | <-------+ bge3 10.9.0.254/24 | +-----------------------+ If Zebra has decided that the route to 192.168.0.1 is shortest through ISP-A, doing a regular traceroute to 192.168.0.1 goes through ISP-A easily. If I want to traceroute to that IP through ISP-B, I use the -s traceroute option to set the source IP address to 10.2.0.2 (to ensure the return path goes through ISP-B, since only ISP-B is announcing that /30's space). If I use the -g option to source route the traceroute through 10.2.0.1, it mostly works, except that if I use source routing, I can't trace route through two of my uplinks since they disable source routing. Even through the one that doesn't, I usually hit a router somewhere along the way that has it disabled. Any ideas? -- Kevin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message