Silent interface

One purpose of the silent interface is for network security.

For a large OSPF network, security must be considered. In OSPF network design, OSPF packets cannot be sent to the end user. This is to prevent end users from detecting OSPF packets. If users can intercept OSPF packets, they can know how to join the OSPF network. In this case, it is easy to destroy the OSPF network. To ensure the security and stability of the OSPF network, use the silent interface on the OSPF network edge device to avoid user-side OSPF packets. The specific method is to run the silent interface command on a perimeter interface to prevent the interface from receiving and sending OSPF packets. After an interface cannot send and receive OSPF packets, the direct route of the interface can still be advertised, but hello packets on the interface are blocked and the neighbor relationship cannot be established on the interface. In this way, the user side cannot detect OSPF packets on the network.

Deactivate all OSPF interfaces to prevent the announcement of unexpected routes and enable the specified interface.

e.g

ospf 1

silent-interface all

undo silent-interface GigabitEthernet1/0/4