For those who want to become (or stay) a Linux security expert.See training package Security scanning with Lynis and Lynis Enterprise Run automated security scans and increase your defenses.The DR will, in turn distribute the update to the non-DR routers.The BDR is just a backup, it acts as a non-DR router unless the DR goes offline.Keep learning So you are interested in Linux security?Join the Linux Security Expert training program, a practical and lab-based training ground.If it was a DR or BDR, it would also belong to the group “OSPFDesignated Routers”.
In order to establish neighbor relationships with other routers, OSPF will send hello messages to the multicast address 188.8.131.52.
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I was inspired by a (relatively) recent post by Jeremy Stretch at that explained OSPF designated router configuration in Cisco IOS.
First, let’s take a look at how the election process works with a basic OSPF configuration.
We can identify pretty quickly how the OSPF network is working by showing OSPF status on the eth0 interface of R2: [email protected]:~$ show ip ospf interface eth0 eth0 is up ifindex 2, MTU 1500 bytes, BW 0 Kbit < UP, BROADCAST, RUNNING, MULTICAST> Internet Address 10.1.1.1/24, Broadcast 10.1.1.255, Area 0.0.0.0 MTU mismatch detection:enabled Router ID 0.0.0.1, Network Type BROADCAST, Cost: 10 Transmit Delay is 1 sec, State DROther, Priority 1 Designated Router (ID) 0.0.0.5, Interface Address 10.1.1.5 Backup Designated Router (ID) 0.0.0.4, Interface Address 10.1.1.4 Multicast group memberships: OSPFAll Routers Timer intervals configured, Hello 10s, Dead 40s, Wait 40s, Retransmit 5 Hello due in 0.257s Neighbor Count is 4, Adjacent neighbor count is 2 [email protected]:~$ As you can see, R1 has detected the DR is R5, shown not only by the router-id that I configured (0.0.0.5) but also by the detected interface IP address 10.1.1.5.