ip ospf authentication-type (for a
      VLAN)
   
   
      Configure the OSPF authentication type for the VLAN. If you choose simple, you must
         configure the password with the ip ospf authentiation-key WORD<0-8> command. If you
         choose MD5, you must configure the MD5 key with the ip ospf message-digest-key
         <1-255> md5 WORD<0-16> command.
    
      Syntax
         
         
            - 
               
                  default ip ospf
                     authentication-type
                
- 
               
                  ip ospf
                     authentication-type message-digest
                
- 
               
                  ip ospf
                     authentication-type none
                
- 
               
                  ip ospf
                     authentication-type sha-1
                
- 
               
                  ip ospf
                     authentication-type sha-2
                
- 
               
                  ip ospf
                     authentication-type simple
                
- 
               
                  no ip ospf
                     authentication-type
                
Command Parameters
         
         
            
               - message-digest
- Configures the authentication-type
                  to message-digest. If you choose MD5, you must configure the MD5 key with the ip
                  ospf message-digest-key <1-255> md5 WORD<0-16> command. Message Digest
                  5 (MD5) provides standards-based authentication using 128-bit encryption. If you
                  use MD5, each OSPF packet has a message digest appended to it. The digest must
                  match between sending and receiving routers, or the packet is discarded.
- none
- Configures the authentication-type
                  to none.
- sha-1
- Configures the authentication-type
                  to secure hash algorithm 1 (SHA-1). SHA-1 provides standards-based authentication
                  using 128-bit encryption.
- sha-2
- sha-2—Specifies SHA-2, which
                  offers the hash function SHA-256.  Note    The command parameter sha-2, an update of SHA-1, can offer six hash
                        functions that include SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224,SHA
                        512/256, with hash values that are 224, 256, 384, or 512 bits. However, the
                        current release supports only SHA-256. 
- simple
- Configures the authentication-type
                  to simple, which is a simple-text password. Only routers that contain the same
                  authentication ID in their LSA can communicate with each other. Using a
                  simple-text password is not a best practice for security. If you choose simple,
                  you must configure the password with the ip ospf authentiation-key
                     WORD<0-8> command. 
Command Mode
         
         VLAN Interface Configuration