110
pop3
TCP · 0x006E
Port 110 — pop3
Port 110 carries Mail retrieval over TCP. Being at or below 1023, only root may open it on Unix. Its encrypted twin is 995.
0–1023. On Unix only root may open one.
Where it sits in 65535
A port number is 16 bits, so it stops at 65535. The narrow band at the left is everything up to 1023.
065535
- Service
- Mail retrieval (pop3)
- Kind
- Protocol
- TCP
- Range
- Well-known
- Root needed
- Yes
- Hexadecimal
- 0x006E
- Binary
- 0000000001101110
- Two bytes
- 0 · 110
- Encrypted twin
- 995
Same kind
Sending mail out and fetching it back.
Ports next to it
How to read this
- A port number is 16 bits, so it runs 0 to 65535. There is no port 65536.
- Opening anything at or below 1023 needs root on Unix.
- Plain and encrypted often live on different numbers — 80 and 443, for one.
- Numbers like 3000 and 8080 were never registered; those are marked as custom.
Frequently asked questions
Q. What is port 110 used for?
Mail retrieval (pop3) uses it, over TCP.
Q. Does opening port 110 need root?
Yes. It is at or below 1023, so on Unix only root may open it.
Q. Which range does port 110 fall in?
Well-known (0–1023). In hex it is 0x006E.
Q. Is there an encrypted version of port 110?
Port 995 does the same thing wrapped in TLS.