how does bird choose primary ip address for ospf?

[Martin Kraus]

Hi. I've just ran into a little problem with bird 1.1.0, but it just might be
a problem with linux. I'm setting ip addresses on interfaces using ifupdown
and /etc/network/interfaces where public ip address gets set up using builtin
configuration parameters(address/netmask) and private ip address(for switches
etc.) gets set up using the "up /sbin/ip address add ...." command. 

I've never had any problems using this setup, since it first sets the public
ip address, which ospf uses, and then sets the private prefix, which just gets
propagated. Today, using the same configuration, bird chose the private ip
address as a primary address for ospf. The ip private ip address was set up as
a second address but using show interfaces in bird client showed the private
ip address as primary:

eth1 up (index=3)
    MultiAccess Broadcast Multicast AdminUp LinkUp MTU=1500
    172.23.17.129/25 (Primary, broadcast 172.23.17.255, scope site)
    212.71.177.129/28 (Unselected, broadcast 212.71.177.143, scope univ)


Could this be an issue with bird, or is it some problem with kernel/ifupdown?

thanks
mk