143
imap
TCP · 0x008F
Port 143 — imap
Port 143 carries Mail access over TCP. Being at or below 1023, only root may open it on Unix. Its encrypted twin is 993.
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 access (imap)
- Kind
- Protocol
- TCP
- Range
- Well-known
- Root needed
- Yes
- Hexadecimal
- 0x008F
- Binary
- 0000000010001111
- Two bytes
- 0 · 143
- Encrypted twin
- 993
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 143 used for?
Mail access (imap) uses it, over TCP.
Q. Does opening port 143 need root?
Yes. It is at or below 1023, so on Unix only root may open it.
Q. Which range does port 143 fall in?
Well-known (0–1023). In hex it is 0x008F.
Q. Is there an encrypted version of port 143?
Port 993 does the same thing wrapped in TLS.