Port 43 — WHOIS
Quick reference for TCP/UDP port 43, used by WHOIS. Includes what the service does, security guidance and related ports.
Port
43
Protocol
TCP
Service
WHOIS
What is port 43?
Domain registration lookup.
What port does WHOIS use?
WHOIS listens on port 43 by default.
Security guidance
Medium risk — open with care
Port 43 (WHOIS) can safely face the internet if you keep the software up to date, restrict admin endpoints, and use TLS where possible. Audit who can reach it and watch your logs.
Frequently asked
What is port 43 used for?+
Port 43 is the standard TCP/UDP port for WHOIS. Domain registration lookup.
What port does WHOIS use?+
WHOIS listens on port 43 by default.
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