You have to modify the esp line in //var/ipfire/vpn/ipsec.conf file. IPSEC Down == esp=aes256-sha1! IPSEC Up == esp=aes256-sha1-modp1536! Exemple of Good IPSec connexion : conn "Name of IPSec Connexion" left=x.x.x.x leftsubnet=x.x.x.x/16 leftfirewall=yes lefthostaccess=yes right=x.x.x.x rightsubnet=x.x.x.x/16 leftid="x.x.x.x" rightid="x.x.x.x" ike=aes256-sha-modp1536! esp=aes256-sha1-modp1536! keyexchange=ikev1 ikelifetime=3h keylife=1h dpdaction=restart dpddelay=30 dpdtimeout=120 authby=secret auto=start fragmentation=yes
Fixed with Core Update 92 *** This bug has been marked as a duplicate of bug 10860 ***