When
show log vpn
the lines are double - with and without systemd.
example
May 27 18:43:00 charon[1998]: 07[NET] <5> received packet: from some_ip[18425] to some_ip[500] (1072 bytes) May 27 18:43:00 charon[1998]: 07[ENC] <5> parsed IKE_SA_INIT request 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(HASH_ALG) ] May 27 18:43:00 charon-systemd[1998]: received packet: from some_ip[18425] to some_ip[500] (1072 bytes) May 27 18:43:00 charon[1998]: 07[IKE] <5> some_ip is initiating an IKE_SA May 27 18:43:00 charon-systemd[1998]: parsed IKE_SA_INIT request 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(HASH_ALG) ] May 27 18:43:00 charon[1998]: 07[CFG] <5> selected proposal: IKE:AES_GCM_16_128/PRF_HMAC_SHA2_256/MODP_2048 May 27 18:43:00 charon-systemd[1998]: some_ip is initiating an IKE_SA May 27 18:43:00 charon[1998]: 07[IKE] <5> remote host is behind NAT May 27 18:43:00 charon-systemd[1998]: selected proposal: IKE:AES_GCM_16_128/PRF_HMAC_SHA2_256/MODP_2048 May 27 18:43:00 charon[1998]: 07[IKE] <5> DH group MODP_4096 unacceptable, requesting MODP_2048 May 27 18:43:00 charon-systemd[1998]: remote host is behind NAT