I have a fairly old FreeBSD 4 box acting as a router. It is the endpoint of a tunnel and there is a /48 subnet routed down this tunnel. By default, the source IPv6 address used by the machine is the address of the local end of the tunnel. This isn't really what I want, particularly since I have no control over the rDNS of this address. In the past I have found a way around this is to not assign an address to the tunnel, and specify the default route with a simple route add -inet6 default -interface gif0 This causes the source address used to be one assigned to one of the NICs, and works fine. However, I guess I can't do this with SIXXS, because if the tunnel end point IPv6 is not assigned to any interface, it will not reply to pings and I'll loose credits. Is there another way to force the default source address to be something from within the subnet, rather than the address of the tunnel endpoint? Or alternatively, can I specify the address to be pinged as one from within the subnet?