Port 2821 is primarily used for communication between email servers using the Simple Mail Transfer Protocol (SMTP) for email delivery. It is commonly referred to as the ESMTP port and is used by mail transfer agents to send, receive, and relay email messages between different email systems.
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 2821 |
tcp |
vrts-at-port |
VERITAS Authentication Service |
REGISTERED PORT |
Port 2821 |
udp |
vrts-at-port |
VERITAS Authentication Service |
REGISTERED PORT |
UnOfficial
Unofficialy or sometimes with conflict, the same port may be used by different applications.
Port | Protocol (TCP/UDP) | Description |