Configuring OSPF MD5 authentication


ip ospf md5-auth-key-chain chainname-string

no ip ospf [ip-address] authentication

Used in the VLAN interface context to configure MD5 authentication for all interfaces in the VLAN or for a specific subnet. The MD5 authentication takes effect immediately, and all OSPF packets transmitted on the interface contain the designated key. All OSPF packets received on the interface are also checked for the key. If it is not present, the packet is dropped.

To disable MD5 authentication on an interface, use the no form of the command.


Before using this authentication option, you must configure one or more key chains on the routing switch by using the Key Management System (KMS). See the access security guide for your switch.

Default: Disabled


Used in subnetted VLAN contexts where you want to assign or remove MD5 authentication associated with a specific subnet.

Omit this option when you want the command to apply to all interfaces configured in the VLAN.


The name of a key generated using the key-chain chain_name key key_id .

To change the MD5 authentication configured on an interface, re-execute the command with the new MD5 key.

Use show ip ospf interface ip-address to view the current authentication setting.


To replace the MD5 method with the password method on a given interface, overwrite the MD5 configuration by using the password form of the command shown in the next syntax description. (It is not necessary to disable the currently configured OSPF MD5 authentication.)

Default: Disabled