Yes, it's a common pitfall, look for "krt_prefsrc" in the doc. Or have a look at
https://dn42.net/howto/bird#Source-address-selection (sorry, certificate seems to have expired) On Thu, Nov 13, 2014 at 11:06:25PM +0100, [email protected] wrote: > Hi! > > I'm working on getting a few linux-routers with bird up and running and I'm > wondering: Is there any way to influence source-address selection for the > routes installed by bird? (how do other bird-users handle this?, I guess I'm > not alone?) > > We have a transit from a provider that doesn't announce the linknet, as a > lot of providers do. (and i shouldn't source traffic from the linknet, i > should use own addresses) > When i source traffic from the server/router it seems linux default-action > is to select the interface closest to the destination which is the > peering-linknet and it happily sends tcp / udp / icmp requests to the world. > The replies never make it back though since the ip isn't reachable from > anywhere else. > > With ip route there seems to be this flag "src <addr>", so you can specify > "ip route add x.x.x.x/y via z.z.z.z src a.a.a.a", this influences the kernel > to select src a.a.a.a when sending traffic to x.x.x.x/y, but i haven't found > such an option in the kernel-table in bird. > > If i have a router where only the "inside"-ip is reachable from the > internet, and all routes point to the outside, how do i make it source all > locally generated traffic from the inside-ip? > > Do you setup multiple routing-tables and set the default-table to direct > traffic to the inside, then on the inside-interface have the full routing > table (would this work?), or how do you handle this? > > Best regards > Oskar Stenman
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