Network ports · 110
110 — POP3
Port 110 is the POP3 mailbox protocol, traditionally download-and-delete.
Key facts
| Port | 110 |
|---|---|
| Transport | TCP |
| Service | POP3 |
| Model | Download, often delete |
| Encryption | STARTTLS via STLS, optional |
| Range | Well-known (0–1023) |
One device, one mailbox
POP3 was designed for a single client that downloads messages and removes them from the server. Folders, flags and server-side search are not part of the model. That makes it simple and efficient on a poor connection, and awkward when the same mailbox is read from a phone and a laptop.
Many clients can leave messages on the server, but the protocol still lacks the folder synchronisation that IMAP provides.
Encryption and port 995
Plain POP3 sends the password in clear text. The STLS command upgrades the connection if the server supports it. POP3S uses implicit TLS on port 995, which is the safer and more common configuration today.
If a client is configured for port 110 without TLS, credentials are exposed. Prefer 995 unless the server is on a trusted local network.
Frequently asked questions
Should I use POP3 or IMAP?
Use IMAP if you read mail on more than one device or need folders. POP3 suits a single-device, archive-and-delete workflow.
What is the encrypted POP3 port?
995 uses implicit TLS. Port 110 can upgrade with STLS but starts in clear text.