hi Ondrej,

Ondrej Zajicek via Bird-users wrote in <ak0CUJw9_GN1C0nu@feanor>:
> On Mon, Jul 06, 2026 at 09:42:35PM +0100, Lexi Winter wrote:
> > i'm using BIRD 3.2.0 on FreeBSD 15.0.  i have a PPPoE interface with a
> > point-to-point IPv4 address configured:
> >[...] 
> > however, BIRD does not advertise 81.187.73.117/32 in OSPF.  it *does* 
> > advertise
> > 81.187.81.187/32, which is the remote side of the interface.
> 
> This is somewhat idiosyncratic BIRD behavior. For point-to-point IPv4
> addresses, BIRD do *not* announce the local one (while the remote one is
> announced only in case of stub interface). This works when one configures
> point-to-point addresses with existing/loopback address of the router. E.g.:
> 
> eth0: 192.168.1.0/24
> eth1: 192.168.1.0/32 --> 192.168.2.0/32
> 
> This is something that i always wanted to fix in some more
> generic/configurable way, but never got to that.
> 
> The workaround is to set the same IP address as /32 on a dummy/loopback
> interface and announce it as a stub.

thanks, this explanation makes sense.  unfortunately, FreeBSD does
not seem to allow an address to be configured as a normal /32 on one
interface and a PtP address on another interface:

        # ifconfig lo1 inet 81.187.73.117/32 alias
        ifconfig: ioctl (SIOCAIFADDR): File exists

(this is different from the normal behaviour, where the same /32 address
can be configured on multiple interfaces; it seems to be specific to PtP
addresses.)

also, since this address is assigned by PPPoE, it is theoretically
possible that it could change -- although in practice it isn't an
issue for me (because it's statically assigned and will never change)
i could imagine this being an issue for some people.

so, it would be nice if there was a configuration option to change this
behaviour, but in the mean time, i'll continue to work around it by
injecting the address as an E2 route.

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