Hi All! I'm a very new bird user, but i have some problems with cisco 7200 router. First, the HELLO packet ignored with "Bad OSPF hello packet from 1.0.0.1 received: options mismatch (0x12)." if i use the cisco default ospf configuration. With "ip ospf lls disable" option everything is ok. Second, i advertise some alias IP from the pc to the cisco router, but if i remove the alias address from the interface some OSPF routes still present in the cisco router. Here is the relevant configuration: Cisco 7200 12.2(28)SB5 interface Loopback0 ip address 3.0.0.1 255.255.255.255 ! interface FastEthernet0/0 ip address 1.0.0.1 255.255.255.0 ip ospf message-digest-key 1 md5 benabela ip ospf lls disable duplex full ! router ospf 1 log-adjacency-changes area 0.0.0.0 authentication message-digest network 1.0.0.0 0.0.0.255 area 0.0.0.0 default-information originate ! ip classless ip route 0.0.0.0 0.0.0.0 Loopback0 Bird 1.1.4 protocol kernel { learn; scan time 20; import all; export none; } protocol device { scan time 10; } protocol ospf ospf1 { debug { routes,filters }; export filter { if net ~ 192.0.2.0/24 then accept; reject; }; area 0.0.0.0 { interface "tap1" { authentication cryptographic; password "benabela"; }; }; }; ip addr show output without alias adresses: 22: tap1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 500 link/ether 00:ff:1a:ea:21:0c brd ff:ff:ff:ff:ff:ff inet 1.0.0.2/24 brd 1.0.0.255 scope global tap1 inet6 fe80::2ff:1aff:feea:210c/64 scope link valid_lft forever preferred_lft forever The tap1 and cisco fa0/0 is bridged. The tap1:0 and tap1:1 alias ip now not present (earlier i up and down the alias interfaces) , but cisco show this: 1.0.0.0/24 is subnetted, 1 subnets C 1.0.0.0 is directly connected, FastEthernet0/0 3.0.0.0/32 is subnetted, 1 subnets C 3.0.0.1 is directly connected, Loopback0 O E2 192.0.2.0/24 [110/10000] via 1.0.0.2, 00:28:35, FastEthernet0/0 S* 0.0.0.0/0 is directly connected, Loopback0 Bird show this: bird> sh route 0.0.0.0/0 via 1.0.0.1 on tap1 [ospf1 17:47] E2 (150/10/1) [1] via 10.1.16.1 on eth0 [kernel1 17:44] (10) 1.0.0.0/24 dev tap1 [direct1 17:44] (240) dev tap1 [ospf1 17:47] I (150/10) 2.0.0.0/24 dev tap2 [direct1 17:44] (240) dev tap2 [ospf2 17:44] I (150/10) 10.1.16.0/20 dev eth0 [direct1 17:44] (240) 127.0.0.0/8 dev lo [direct1 17:44] (240) 192.168.252.0/24 dev vmnet2 [direct1 17:44] (240) 192.168.253.0/24 dev vmnet1 [direct1 17:44] (240) 192.168.254.0/24 dev vmnet8 [direct1 17:44] (240) If i up the tap1:0 and tap1:1 22: tap1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 500 link/ether 00:ff:1a:ea:21:0c brd ff:ff:ff:ff:ff:ff inet 1.0.0.2/24 brd 1.0.0.255 scope global tap1 inet 192.0.2.1/32 brd 192.0.2.255 scope global tap1:0 inet 192.0.2.2/32 brd 192.0.2.255 scope global tap1:1 inet6 fe80::2ff:1aff:feea:210c/64 scope link valid_lft forever preferred_lft forever bird show this: bird> show route 0.0.0.0/0 via 1.0.0.1 on tap1 [ospf1 17:47] E2 (150/10/1) [1] via 10.1.16.1 on eth0 [kernel1 17:44] (10) 1.0.0.0/24 dev tap1 [direct1 17:44] (240) dev tap1 [ospf1 17:47] I (150/10) 2.0.0.0/24 dev tap2 [direct1 17:44] (240) dev tap2 [ospf2 17:44] I (150/10) 10.1.16.0/20 dev eth0 [direct1 17:44] (240) 127.0.0.0/8 dev lo [direct1 17:44] (240) 192.168.252.0/24 dev vmnet2 [direct1 17:44] (240) 192.168.253.0/24 dev vmnet1 [direct1 17:44] (240) 192.168.254.0/24 dev vmnet8 [direct1 17:44] (240) 192.0.2.1/32 dev tap1 [direct1 18:26] (240) 192.0.2.2/32 dev tap1 [direct1 18:27] (240) cisco show this: 1.0.0.0/24 is subnetted, 1 subnets C 1.0.0.0 is directly connected, FastEthernet0/0 3.0.0.0/32 is subnetted, 1 subnets C 3.0.0.1 is directly connected, Loopback0 192.0.2.0/24 is variably subnetted, 3 subnets, 2 masks O E2 192.0.2.2/32 [110/10000] via 1.0.0.2, 00:00:40, FastEthernet0/0 O E2 192.0.2.0/24 [110/10000] via 1.0.0.2, 00:00:40, FastEthernet0/0 O E2 192.0.2.1/32 [110/10000] via 1.0.0.2, 00:00:40, FastEthernet0/0 S* 0.0.0.0/0 is directly connected, Loopback0 Down the tap alias interfaces: bird> show route 0.0.0.0/0 via 1.0.0.1 on tap1 [ospf1 17:47] E2 (150/10/1) [1] via 10.1.16.1 on eth0 [kernel1 17:44] (10) 1.0.0.0/24 dev tap1 [direct1 17:44] (240) dev tap1 [ospf1 17:47] I (150/10) 2.0.0.0/24 dev tap2 [direct1 17:44] (240) dev tap2 [ospf2 17:44] I (150/10) 10.1.16.0/20 dev eth0 [direct1 17:44] (240) 127.0.0.0/8 dev lo [direct1 17:44] (240) 192.168.252.0/24 dev vmnet2 [direct1 17:44] (240) 192.168.253.0/24 dev vmnet1 [direct1 17:44] (240) 192.168.254.0/24 dev vmnet8 [direct1 17:44] (240) But cisco still present some bad routes: 1.0.0.0/24 is subnetted, 1 subnets C 1.0.0.0 is directly connected, FastEthernet0/0 3.0.0.0/32 is subnetted, 1 subnets C 3.0.0.1 is directly connected, Loopback0 O E2 192.0.2.0/24 [110/10000] via 1.0.0.2, 00:04:18, FastEthernet0/0 S* 0.0.0.0/0 is directly connected, Loopback0 So what is the problem? Some debug output from bird: bird: ospf1 < added 192.0.2.0/24 dev tap1 bird: ospf1 < removed 192.0.2.0/24 dev tap1 bird: ospf1 < added 192.0.2.1/32 dev tap1 bird: ospf1 < removed 192.0.2.1/32 dev tap1 bird: ospf1 < added 192.0.2.0/24 dev tap1 bird: ospf1 < removed 192.0.2.0/24 dev tap1 bird: ospf1 < added 192.0.2.0/24 dev tap1 bird: ospf1 < removed 192.0.2.0/24 dev tap1 bird: ospf1 < added 192.0.2.2/32 dev tap1 bird: ospf1 < removed 192.0.2.1/32 dev tap1 bird: ospf1 < removed 192.0.2.2/32 dev tap1 So why produced bird these lines with /24 prefix?: bird: ospf1 < added 192.0.2.0/24 dev tap1 bird: ospf1 < removed 192.0.2.0/24 dev tap1 Thx Csszep