Date: Tue, 10 Mar 2015 14:40:38 +0000 From: Joe Holden <mail@m.jwh.me.uk> To: freebsd-net@freebsd.org Subject: Re: FreeBSD responding with wrong receiving interface IP Message-ID: <54FF0266.3080106@m.jwh.me.uk> In-Reply-To: <B70E1152-E492-4B38-B2EE-A5DBF246DEF7@neville-neil.com> References: <54FE566F.5030607@winterei.se> <B70E1152-E492-4B38-B2EE-A5DBF246DEF7@neville-neil.com>
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On 10/03/2015 13:16, George Neville-Neil wrote: > On 10 Mar 2015, at 11:26, Paul S. wrote: > >> 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. > > I wonder if we could see some routing tables? That might help. > > Best, > George sysctl net.inet.icmp.reply_from_interface=1 will probably do what you expect.
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