Port 203 is typically used for the AppleTalk Zone Information Protocol (ZIP) in the AppleTalk networking protocol suite. This port allows devices in an AppleTalk network to exchange information about the zones (logical groups of network devices) they belong to. However, this protocol has become obsolete, and the use of Port 203 has declined rapidly.
Ports those registered with IANA are shown as official ports. The same port number may be unofficialy used by various services or applications. The official usage are listed separately below its usage may change from time to time.
Official
Port |
Protocol (TCP/UDP) |
Title |
Description |
Port Type |
Port 203 |
tcp |
at-3 |
AppleTalk Unused |
WELL KNOWN PORT |
Port 203 |
udp |
at-3 |
AppleTalk Unused |
WELL KNOWN PORT |
UnOfficial
Unofficialy or sometimes with conflict, the same port may be used by different applications.
Port | Protocol (TCP/UDP) | Description |