Malformed and unexpected packets
An OSPF packet is considered malformed and is discarded
if any of the following are present in the packet:
- Incorrect version in the OSPF packet header.
- Incorrect packet type in the OSPF header.
- Incorrect length value in the OSPF packet header.
- Incorrect checksum in the OSPF packet header.
- Incorrect LSA type in an LSA header.
- Incorrect length value in an LSA header.
- Incorrect checksum in an LSA header.
- Incorrect LSA age field in an LSA header.
- Incorrect LSA scope value in an LSA header.
- Incorrect prefix length value in an LSA that includes address prefixes.
- Incorrect value for the number of entries in a packet or LSA. For example, a bad number of LSAs value in a Link State Update packet, a bad number of links value in a Router LSA, or a bad number of prefixes value in a Link LSA or Intra-Area Prefix LSA.
An OSPF packet is considered unexpected and is discarded
if any of the following are present in the packet:
- Unexpected AS External LSA received over an interface that is attached to an OSPF stub area.
- Unexpected AS External LSA received over a virtual link.
- Unexpected AS Scope LSA received over an interface that is attached to an OSPF stub area.