Prevent duplicate routes with OSPF

19 Jun 2019

      Hi list,

This is probably a question that was answered many times before: how can
I prevent duplicate routes originating from OSPF?

For example, a routing table with BIRD2 shut down:
...
# ip r s
default via 192.168.255.1 dev eth0
192.168.255.0/24 dev eth0 proto kernel scope link src 192.168.255.82
And... with BIRD2 running:
...
# ip r s
default via 192.168.255.1 dev eth0
1.2.3.4 dev dummy0 proto bird scope link metric 32
1.2.3.7 via 192.168.255.213 dev eth0 proto bird metric 32
192.168.255.0/24 dev eth0 proto kernel scope link src 192.168.255.82
192.168.255.0/24 dev eth0 proto bird scope link metric 32
In this example at least 192.168.255.0/24 is a duplicate.

Configuration used:
...
log syslog all;
protocol device {
}
protocol direct {
    disabled;        # Disable by default
    ipv4;            # Connect to default IPv4 table
    ipv6;            # ... and to default IPv6 table
}
protocol kernel {
    ipv4 {            # Connect protocol to IPv4 table by channel
        export all;    # Export to protocol. default is export none
    };
}
protocol kernel {
    ipv6 {            # Connect protocol to IPv4 table by channel
        export all;    # Export to protocol. default is export none
    };
}
protocol static {
    ipv4;            # Again, IPv4 channel with default options
}
protocol static {
    ipv6;
}
protocol ospf v2 foobar {
    area 0.0.0.0 {
        interface "dummy0" {
            stub;
        };
        interface "eth0" {
        };
    };
}
How can I prevent direct connected routes from showing up from OSPF as
well ending up in duplicates?

Thanks in advance!

Regards,
Kees

-- 
https://nefos.nl/contact

Nefos IT bv
Ambachtsweg 25 (industrienummer 4217)
5627 BZ Eindhoven
Nederland

KvK 66494931

/Aanwezig op maandag, dinsdag, woensdag en vrijdag/

Prevent duplicate routes with OSPF

Kees Meijs