Hello, being a bird 1.6 user (Debian), I find myself often in the situation that I'd like to define a variable in either bird.conf or bird6.conf and have a general.conf that defines the filters used in both protocols. However if I have a variable, for instance net_prefer_provider_a = [ s.o.m.e/prefix+ ]; in bird6.conf, but not don't prefer IPv4 traffic from any network of this provider, I'd like to define net_prefer_provider_a = []; However this is not supported in bird1.6. Now I tried to get around this problem by using defined(), however this code also does not work: if defined(net_prefer_to_a) then { if net ~ net_prefer_to_a then { bgp_local_pref = pref_high; } } net_prefer_to_a is defined in IPv6, but not in IPv4. This gives the error message: /etc/bird/general.conf:128:40 net_prefer_to_a: variable expected. How do you handle default or empty values for sets of prefixes? Best, Nico -- Your Swiss, Open Source and IPv6 Virtual Machine. Now on www.datacenterlight.ch.