Port 500 — IPsec ISAKMP
Quick reference for TCP/UDP port 500, used by IPsec ISAKMP. Includes what the service does, security guidance and related ports.
Port
500
Protocol
UDP
Service
IPsec ISAKMP
What is port 500?
IPsec key exchange.
What port does IPsec ISAKMP use?
IPsec ISAKMP listens on port 500 by default.
Security guidance
Medium risk — open with care
Port 500 (IPsec ISAKMP) 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.
Related ports
Frequently asked
What is port 500 used for?+
Port 500 is the standard TCP/UDP port for IPsec ISAKMP. IPsec key exchange.
What port does IPsec ISAKMP use?+
IPsec ISAKMP listens on port 500 by default.
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