Manual IPsec: Advanced Options
ADVANCED: These settings are meant to be configured by advanced users with networking knowledge. They apply to phase 1 and phase 2 of the IPsec process.
Key Exchange Version: Select either IKEv1 or IKEv2.
Encryption: Select AES-128, AES-256, or 3DES encryption.
Hash: Select either SHA1 or MD5
DH (Diffie-Hellman) Group: DH Groups 2, 5, 14, 15, 16, 19, 20, 21, 25, 26 are available.
PFS (Perfect Forward Secrecy): Enable or disable. When PFS is enabled the phase 2 DH group is hardcoded to the same group that is selected in DH Group.
Dynamic Routing: Enable or disable the use of a virtual tunnel interface (VTI). This will specify that the VPN configuration is either policy based (off) or route based (on). (Note: manual VPN VTI interfaces start with vti64 and increment as vti65, vti66, etc. as more manual VPNs are added)
NOTE: The use of larger algorithms is more secure, but they come with the cost of a CPU overhead increase. For example, AES-256 will use more CPU resources than AES-128. AES-128 is the recommended encryption for most use-cases.