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Port 4500: IPsec NAT traversal

Common Ports Reference: What runs on port 3389, 445 or 5985: common TCP and UDP ports for web, mail, Windows, AD, databases and VPNs, with security notes.

The ports that come up when opening a firewall, reading a scan or troubleshooting a connection: what runs on each, TCP or UDP, and what to watch out for. Search by number or name. Port numbers and service names were checked against IANA's port number registry; ports that are widely used but assigned by IANA to something else are marked unofficial.

Port number or name

4500 is a registered port (1024-49151): assigned by IANA on request. IANA's registry lists everything assigned to it: look up 4500 at IANA.

1 of 96 ports

DNS, DHCP, time, SNMP, logging and VPNs.

PortProtocolServiceWhat it's forIANA name
4500
UDP
IPsec NAT traversal
IPsec through NAT routers, needed by most VPN clients.
ipsec-nat-t

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