Port 123 — NTP
Network Time Protocol — synchronizes clocks across devices.
| Port number | 123 |
|---|---|
| Service | NTP |
| Transport | UDP |
| Category | Network |
Is port 123 safe?
Historically abused for amplification DDoS; restrict open NTP servers.
Frequently asked questions
What is port 123 used for?
Port 123 (UDP) is the standard port for NTP. Network Time Protocol — synchronizes clocks across devices.
Is port 123 safe to open?
Historically abused for amplification DDoS; restrict open NTP servers.
Is port 123 TCP or UDP?
Port 123 commonly uses UDP.