Information
Enable OSPF Passive Interfaces
The OSPF Passive Interface feature is used to prevent OSPF from forming neighbor relationships or exchanging Hello packets on specified interfaces, while still allowing the connected subnet to be advertised in the OSPF routing domain. This enhances network security by avoiding unauthorized OSPF adjacencies, reduces unnecessary control traffic, and optimizes resource utilization by limiting OSPF operations to only required interfaces. It is particularly useful for interfaces connected to end-user devices or untrusted networks, improving network stability and simplifying management
Solution
Configure all OSPF enabled interfaces to be passive in OSPF router context
OSPF -
switch(config)# router ospf <OSPF Process ID>
switch(config-ospf-<Process ID>)# passive-interface default
OSPFv3 -
switch(config)# router ospfv3 <OSPF Process ID>
switch(config-ospfv3-<Process ID>)# passive-interface default
The passive interface is then removed from each interface where OSPF neighbor relationships areallowed. Since this is an interface-level configuration change, it can be done from the interface context:
To disable passive interface from selective interfaces -
OSPF -
switch(config)# interface <interface ID>
switch(config-if)# no ip ospf passive
OSPFv3 -
switch(config)# interface <interface ID>
switch(config-if)# no ipv6 ospfv3 passive
Impact:
To limit where OSPF can learn neighbors, AOS-CX supports the passive OSPF interfaces. A passive OSPFinterface has its IP subnets announced, but it does not establish neighbor relationships with other OSPFdevices on the interface.You must make all OSPF enabled interfaces passive. Setting the OSPF enabled interfaces to from defaultto passive is done in the OSPF router instance context.The passive interface is then removed from each interface where OSPF neighbor relationships areallowed. Since this is an interface-level configuration change, it can be done from the interface context