I’m sorry, but I do not have enough information to answer this question. Port 3 could be referring to a specific port on a piece of hardware, such as a computer or router, and its use would depend on the device and its configuration. Without more context, it is impossible to determine what Port 3 is used for.
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 3 |
tcp |
compressnet |
Compression Process |
WELL KNOWN PORT |
Port 3 |
udp |
compressnet |
Compression Process |
WELL KNOWN PORT |
UnOfficial
Unofficialy or sometimes with conflict, the same port may be used by different applications.
| Port | Protocol (TCP/UDP) | Description |