Date: Tue, 10 Mar 2015 11:26:55 +0900 From: "Paul S." <contact@winterei.se> To: freebsd-net <freebsd-net@freebsd.org> Subject: FreeBSD responding with wrong receiving interface IP Message-ID: <54FE566F.5030607@winterei.se>
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Hi, I've been deploying FreeBSD as customer edge routers for customers with sites that do not require high throughput (>1g/s). Each site has two ISPs (Mostly Telstra + Verizon/Optus), and take full routes via OpenBGPd and BIRD. I use next-hop self on all received routes. The FreeBSD boxes have static routes delegating the announced IP blocks to a L3 switch down the road. i.e: route add -net 10.100.1.0/24 10.0.0.1, and then that /24 is originated via BGP to both upstreams. Things in general work fine, but I've been receiving reports of 'weird traceroute results' from my customers. Examples of this would be, 1 some.random.isp (...) (...) 2 gigabitethernet3-3.exi1.melbourne.telstra.net (203.50.77.49) 0.309 ms 0.284 ms 0.227 ms 3 bundle-ether3-100.exi-core10.melbourne.telstra.net (203.50.80.1) 1.966 ms 1.675 ms 1.852 ms 4 bundle-ether12.chw-core10.sydney.telstra.net (203.50.11.124) 16.707 ms 15.917 ms 16.360 ms 5 customer-gw.syd.ALTER.net (...) (...) This traceroute seems to claim that the packet was received over the Verizon gateway, which in reality it was not -- it was received directly over the Telstra interface, but my outbound AS-PATH towards some.random.isp uses Verizon. So FreeBSD replies back with the Verizon address. Another person having the same issue (mostly, but on OpenBSD) can be found at http://openbsd.7691.n7.nabble.com/BGP-responding-with-wrong-IP-address-td90264.html I would love to know if there's a way to fix this, or if I've missed something, or if there's something wrong in the way I set it up. Thank you for taking the time to read.
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