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I'm setting up some servers that will run virtual machines using IPv6. The network topology is something like this, where the br0 interfaces are virtual:

 2001:db8:fedc:aaaa::/64 ---+----------------------------------+--- | | | eth0: 2001:db8:fedc:aaaa::1 | eth0: 2001:db8:fedc:aaaa::2 +----+----+ +----+----+ | server1 | | server2 | +----+----+ +----+----+ | br0: 2001:db8:fedc:abcd::1 | br0: 2001:db8:fedc:cdef::1 | | | VM network 1: | VM network 2: | 2001:db8:fedc:abcd::/64 | 2001:db8:fedc:cdef::/64 +----+----+ +----+----+ | | | | | | vm1 vm2 vm3 vm4 vm5 vm6 

I'm trying to avoid using the network's default gateway to route the packets from a VM in a server to one in another server, because with many hosts it would become a bottleneck.

The idea is then to have each server advertise a route to its own VM network to the other servers. So in the example above, server1 would advertise a route to 2001:db8:fedc:abcd::/64 and server2 to 2001:db8:fedc:cdef::/64.

I have this in server1's radvd.conf:

interface eth0 { AdvSendAdvert on; prefix 2001:db8:fedc:abcd::/64 { }; route 2001:db8:fedc:abcd::/64 { }; }; 

And this is server2's:

interface eth0 { AdvSendAdvert on; prefix 2001:db8:fedc:cdef::/64 { }; route 2001:db8:fedc:cdef::/64 { }; }; 

I can see this information being received from one of the servers if I run "rdisc6 eth0" on the other one, but for some reason the route isn't being added to its routing table.

What am I missing here?

2 Answers 2

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This configuration won't work with radvd, and my attempts came from a misunderstanding of the purpose of router advertisements. This protocol is meant for host autoconfiguration and not for route propagation between routers.

Replacing radvd with Quagga and an IPv6-enabled routing protocol solves the issue.

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The route stanza isn't needed in this case since by virtue of advertising the prefix, your system should be autoconfiguring the link-local address of server[1,2] as it is the server that tendered the route advertisement. It's possible that adding the route stanza for the same subnet is colliding with the route addition.

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