Is it possible to use as hash algorithm a value of "null" in JunOS, as in the following command of ScreenOS:
set ike p2-proposal "g5-esp-aes256-no_auth-900s" group5 esp aes256 null second 900
Setting NULL encryption means actually not setting any encryption-algorithm under IPsec proposals.
Refer to the following link:
Note: It's not supported in FIPS mode .