Hi everyone I apologise in advance, english is not my native language... For study purpose, I'm trying to setup OSPFv2 between Bird 1.6.6 and a Cisco router. It seems there is a problem with the auth-type code send by Bird in the ospf hello packets. This problem prevent the devices to become neighbours. Here is the configuration of the Cisco router : router ospf 1 no capability lls network 192.168.42.0 0.0.0.255 area 0.0.0.0 interface Vlan10 description Management ip address dhcp ip ospf authentication ip ospf authentication-key azerty ip ospf dead-interval 6 ip ospf hello-interval 2 And the configuration of Bird : router id 1.1.1.1; protocol device { } protocol kernel { metric 64; import all; export all; } protocol ospf test { instance id 42; area 0.0.0.0 { interface "eth*" { hello 2; dead count 3; authentication simple; password "azerty"; }; }; export all; } If I launch the debug command on the Cisco, I see this : Mar 23 18:09:59: OSPF-1 PAK : Vl10: OUT: 192.168.42.43->224.0.0.5: ver:2 type:1 len:44 rid:192.168.42.43 area:0.0.0.0 chksum:2720 auth:1 Mar 23 18:09:59: OSPF-1 PAK : Vl10: IN: 192.168.42.73->224.0.0.5: ver:2 type:1 len:52 rid:1.1.1.1 area:0.0.0.0 chksum:F0CE auth:10753 Bird send the field auth-type with the value 10753. Tcpdump show the same value : 17:13:38.012494 IP (tos 0xc0, ttl 1, id 21850, offset 0, flags [none], proto OSPF (89), length 64) 192.168.42.43 > 224.0.0.5: OSPFv2, Hello, length 44 Router-ID 192.168.42.43, Backbone Area, Authentication Type: simple (1) Simple text password: azerty 17:13:38.012792 IP (tos 0xc0, ttl 1, id 7301, offset 0, flags [none], proto OSPF (89), length 72) 192.168.42.73 > 224.0.0.5: OSPFv2, Hello, length 52 Router-ID 1.1.1.1, Backbone Area, Authentication Type: unknown (10753) Can you tell me what I'm doing wrong ? If I try the "none" authentication, Bird send the code 10752 and the problem is the same... Thx !