109
pop2
TCP · 0x006D
Port 109 — pop2
Port 109 carries Post Office Protocol 2 over TCP. Being at or below 1023, only root may open it on Unix.
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
- Post Office Protocol 2 (pop2)
- Kind
- Protocol
- TCP
- Range
- Well-known
- Root needed
- Yes
- Hexadecimal
- 0x006D
- Binary
- 0000000001101101
- Two bytes
- 0 · 109
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 109 used for?
Post Office Protocol 2 (pop2) uses it, over TCP.
Q. Does opening port 109 need root?
Yes. It is at or below 1023, so on Unix only root may open it.
Q. Which range does port 109 fall in?
Well-known (0–1023). In hex it is 0x006D.
Q. Does port 109 have a twin?
Not a separate one. It either was encrypted from the start or negotiates TLS on the same number.