Canon LBP6780x Manual page 730

When setting automatically
Select the [Auto] check box.
When setting manually
Set the following items.
[Authentication]
[Encryption]
[DH Group]
9
Set the PFS for [IPSec Network Settings] and [Validity].
(1) When using PFS, select the [Use PFS] check box.
(2) Set [Validity].
When specifying by time
Select the authentication algorithm from [SHA1], [MD5] or [SHA1 and MD5].
Select the encryption algorithm from [3DES-CBC], [AES-CBC] or [3DES-CBC and AES-CBC].
Select the Diffie-Hellman group from [Group 1 (768)], [Group 2 (1024)] or [Group 14 (2048)].