Hi, I have pc router with bird and mikrotik router, ospf routing is configured and working. On mikrotik router I have in log message with every received hello packet "mismatch in network mask - mine 255.255.255.252, remote 255.255.255.248" This messages appears when I have on pc router two IP adress on one interface - one is public 77.x.x.x/30, second is privat 172.16.0.1/29 .When I remove privat ip adress, then messages in mikrotik routers disappears. there is a part of bird.conf interface "vlan10" { cost 10; priority 1; authentication none; type nonbroadcast; strict nonbroadcast yes; neighbors { 77.x.x.x; }; poll 10; retransmit 5; transmit delay 1; hello 10; dead 40; wait 40; }; Thank you for hint