A.proxy-ID B.phase 2 proposal C.Diffie-Hellman group key D.security protocol (ESP or AH)
A.proxy-ID B.preshared key C.Diffie-Hellman group key D.main or aggressive mode
A.message 1 and 2 B.message 3 and 4 C.message 5 and 6 D.message 7 and 8