IPsec VPN
The IETF standard for authenticating and encrypting IP packets.
How widely is it used?
Among the most widely deployed options in 2026Universal for site-to-site and cloud tunnels — every firewall vendor speaks it.
How it works
IKE negotiates security associations and keys; ESP then encrypts and authenticates each packet, in transport mode between hosts or tunnel mode between gateways.
Connects
Device/network → device/network
Protocols
IKEv2, ESP, AH
Typical users
Enterprises, ISPs, Cloud providers
Main use case
Both site-to-site links and standards-based remote access.
Advantages
- Implemented by every serious network vendor
- Hardware offload is common
- Well-audited standard
Limitations
- Many knobs, many ways to misconfigure
- NAT traversal needs care