stupid question about OSPF cost and route preference
Eugene M. Zheganin
emz at norma.perm.ru
Tue Apr 7 15:41:37 CEST 2020
Hello.
I have a bunch of birder routers, and the troublesome router is
connected to some of them via LAN and to some of them via WAN tunnels.
For some reason it always chooses a WAN route, regardless of it's metric:
===Cut===
bird> show route for 10.50.3.0/24
10.50.3.0/24 via 172.16.0.45 on gif1 [ospfv4 18:25:39] * E2
(150/10222/10000) [192.168.57.254]
[root at gw /usr/local/etc]# ifconfig gif1 down
[root at gw /usr/local/etc]# birdc
BIRD 1.6.6 ready.
bird> show route for 10.50.3.0/24
10.50.3.0/24 via 192.168.57.254 on vlan57 [ospfv4 18:33:37] * E2
(150/11/10000) [192.168.57.254]
[root at gw /usr/local/etc]# ifconfig gif1 up
[root at gw /usr/local/etc]# birdc
BIRD 1.6.6 ready.
bird> show route for 10.50.3.0/24
10.50.3.0/24 via 172.16.0.45 on gif1 [ospfv4 18:34:01] * E2
(150/10222/10000) [192.168.57.254]
bird>
===Cut===
And I totally don't understand why (OSPF cost is several times higher !).
Config is as follows:
=== Cut===
filter importospfv4 {
if net ~ [ 10.8.1.0/24 ] then {
reject;
} else {
accept;
}
}
filter exportospfv4 {
if net ~ [ 192.168.55.254/32, 192.168.57.2/32 ] then {
reject;
} else {
accept;
}
}
protocol ospf ospfv4 {
export filter exportospfv4;
import filter importospfv4;
area 0.0.0.0 {
interface "vlan55" {
cost 11;
};
interface "vlan57" {
cost 11;
};
};
area 0.0.0.1 {
interface "gif0"{
cost 5111;
};
interface "gif1" {
cost 5111;
};
};
}
===Cut===
Thanks.
Eugene.
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