Hello, Until a week ago a user with Windows 10 had no issue connecting to the StrongSwan server. But now out of the blue, he can't connect to the StrongSwan server anymore.
The log on the server is: May 7 12:31:06 vpn-p1 charon: 08[IKE] received proposals inacceptable May 7 12:31:06 vpn-p1 charon: 08[ENC] generating IKE_SA_INIT response 0 [ N(NO_PROP) ] May 7 12:31:06 vpn-p1 charon: 08[NET] sending packet: from xxx.x.xx.92[500] to 91.98.xxx.xxx[500] (36 bytes) May 7 12:32:09 vpn-p1 systemd[1]: Started Session 35 of user root. May 7 12:46:21 vpn-p1 systemd[1]: Starting Cleanup of Temporary Directories... May 7 12:46:21 vpn-p1 systemd-tmpfiles[7016]: [/usr/lib/tmpfiles.d/var.conf:14] Duplicate line for path "/var/log", ignoring. May 7 12:46:21 vpn-p1 systemd[1]: Started Cleanup of Temporary Directories. May 7 13:00:13 vpn-p1 systemd[1]: Starting Certbot... May 7 13:00:13 vpn-p1 systemd[1]: Started Certbot. May 7 13:08:20 vpn-p1 systemd[1]: Started Session 36 of user root. May 7 13:11:27 vpn-p1 charon: 12[NET] received packet: from 91.98.xxx.xxx[500] to xxx.x.xx.92[500] (624 bytes) May 7 13:11:27 vpn-p1 charon: 12[ENC] parsed IKE_SA_INIT request 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) V V V V ] May 7 13:11:27 vpn-p1 charon: 12[IKE] received MS NT5 ISAKMPOAKLEY v9 vendor ID May 7 13:11:27 vpn-p1 charon: 12[IKE] received MS-Negotiation Discovery Capable vendor ID May 7 13:11:27 vpn-p1 charon: 12[IKE] received Vid-Initial-Contact vendor ID May 7 13:11:27 vpn-p1 charon: 12[ENC] received unknown vendor ID: 01:52:8b:bb:c0:06:96:12:18:49:ab:9a:1c:5b:2a:51:00:00:00:02 May 7 13:11:27 vpn-p1 charon: 12[IKE] 91.98.xxx.xxx is initiating an IKE_SA May 7 13:11:27 vpn-p1 charon: 12[CFG] received proposals: IKE:AES_CBC_256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_2048, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048, IKE:AES_CBC_256/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_2048 May 7 13:11:27 vpn-p1 charon: 12[CFG] configured proposals: IKE:AES_GCM_16_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_521, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_384, IKE:AES_CBC_256/3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024 May 7 13:11:27 vpn-p1 charon: 12[IKE] remote host is behind NAT May 7 13:11:27 vpn-p1 charon: 12[IKE] received proposals inacceptable May 7 13:11:27 vpn-p1 charon: 12[ENC] generating IKE_SA_INIT response 0 [ N(NO_PROP) ] May 7 13:11:27 vpn-p1 charon: 12[NET] sending packet: from xxx.x.xx.92[500] to 91.98.xxx.xxx[500] (36 bytes) May 7 13:11:28 vpn-p1 charon: 16[NET] received packet: from 91.98.xxx.xxx[500] to xxx.x.xx.92[500] (624 bytes) May 7 13:11:28 vpn-p1 charon: 16[ENC] parsed IKE_SA_INIT request 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) V V V V ] May 7 13:11:28 vpn-p1 charon: 16[IKE] received MS NT5 ISAKMPOAKLEY v9 vendor ID May 7 13:11:28 vpn-p1 charon: 16[IKE] received MS-Negotiation Discovery Capable vendor ID May 7 13:11:28 vpn-p1 charon: 16[IKE] received Vid-Initial-Contact vendor ID May 7 13:11:28 vpn-p1 charon: 16[ENC] received unknown vendor ID: 01:52:8b:bb:c0:06:96:12:18:49:ab:9a:1c:5b:2a:51:00:00:00:02 May 7 13:11:28 vpn-p1 charon: 16[IKE] 91.98.xxx.xxx is initiating an IKE_SA May 7 13:11:28 vpn-p1 charon: 16[CFG] received proposals: IKE:AES_CBC_256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_2048, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048, IKE:AES_CBC_256/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_2048 May 7 13:11:28 vpn-p1 charon: 16[CFG] configured proposals: IKE:AES_GCM_16_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_521, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_384, IKE:AES_CBC_256/3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024 May 7 13:11:28 vpn-p1 charon: 16[IKE] remote host is behind NAT May 7 13:11:28 vpn-p1 charon: 16[IKE] received proposals inacceptable May 7 13:11:28 vpn-p1 charon: 16[ENC] generating IKE_SA_INIT response 0 [ N(NO_PROP) ] May 7 13:11:28 vpn-p1 charon: 16[NET] sending packet: from xxx.x.xx.92[500] to 91.98.xxx.xxx[500] (36 bytes) The Server's ipsec.conf is: config setup strictcrlpolicy=yes uniqueids=never conn roadwarrior auto=add compress=no type=tunnel keyexchange=ikev2 fragmentation=yes forceencaps=yes ike=aes256gcm16-sha256-ecp521,aes256-sha256-ecp384,aes256-3des-sha1-modp1024! esp=aes256gcm16-sha256,aes256-3des-sha256-sha1! dpdaction=clear dpddelay=180s rekey=no left=%any leftid=@${VPNHOST} leftcert=cert.pem leftsendcert=always leftsubnet=0.0.0.0/0 right=%any rightid=%any rightauth=eap-radius eap_identity=%any rightdns=208.67.222.222,208.67.220.220 rightsourceip=${VPNIPPOOL} rightsendcert=never Have the supported ike/esp proposals somehow been changed recently after a recent Windows 10 update? I have made these changes on the Windows 10, after googling for a solution: - The firewall on Windows 10 is currently disabled. - I have set NegotiateDH2048_AES256 = 1 in Regedit - AssumeUDPEncapsulationContextOnSendRule = 2 in Regedit I can't think of anything else I could do on the Windows 10 client. According to my notes, these are the proposed protocols for Windows 10: # these ike and esp settings are tested on Mac 10.12, iOS 10 and Windows 10 # iOS/Mac with appropriate configuration profiles use AES_GCM_16_256/PRF_HMAC_SHA2_256/ECP_521 # Windows 10 uses AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_384 Is there a website that translates AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_384 into the right naming for ipsec.conf so that I enter them under ike and esp respectively? I can't quite make out if I have these settings there or not. If you have any other advice, please help me. Many Thanks,