Port 4500

Q: What is port 4500?

IPsec NAT traversal — allows IPsec through NAT routers UDP port 4500 is used for IPsec NAT traversal (NAT-T), enabling IPsec VPN tunnels to function correctly when the client is behind a NAT router. It encapsulates ESP packets in UDP to pass through NAT devices. It is used alongside port 500 (IKE) by IKEv2/IPsec VPNs. IKEv2 with ports 500 and 4500 is the default built-in VPN protocol on iOS, macOS, and Windows.

IKEv2-NAT-T

IPsec NAT traversal — allows IPsec through NAT routers

Port

4500

Protocol

UDP

Service

IKEv2-NAT-T

Security

Safe

Full name: IKEv2 / IPsec NAT Traversal

What is port 4500?

UDP port 4500 is used for IPsec NAT traversal (NAT-T), enabling IPsec VPN tunnels to function correctly when the client is behind a NAT router. It encapsulates ESP packets in UDP to pass through NAT devices. It is used alongside port 500 (IKE) by IKEv2/IPsec VPNs. IKEv2 with ports 500 and 4500 is the default built-in VPN protocol on iOS, macOS, and Windows.

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