This read-only counter tracks input PDUs discarded specifically because of errors in the CLNP header itself, including bad checksums, a version mismatch, an exceeded lifetime field, or errors found while processing header options. An admin watching this counter climb would suspect a misconfigured or malfunctioning peer generating malformed CLNP packets, or packets that have simply expired in transit. For example, a steady trickle of header errors tied to lifetime-exceeded conditions might prompt the admin to raise clnpDefaultLifeTime if legitimate traffic is expiring before reaching its destination.