Abstract: A network address-port translation (NAPT) apparatus and method for IP packets with a same identification is disclosed. The IP packets at least include a first packet with Layer 4 information and a second packet without Layer 4 information. The NAPT apparatus includes: a packet translation unit for performing a NAPT operation for the first packet to generate a translation IP; and a translation table for storing a correspondence between the same identification and the translation IP. The packet translation unit translates one of a source IP and a destination IP of the second packet into the translation IP according to a forwarding direction of the second packet and the translation table.