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    Houman,<br>
    <br>
         No need to configure a prf, it is already assumed when you
    configured a DH group; so you can drop prfsha256. And as Christian
    suggested, if all your clients support strong encryption  drop all
    weak algorithms/proposals from  the server end i.e 3des, sha1,
    modp1024. I can't believe that  Microsoft still in 2018 offer these
    as the default options and expects users to go tinker with obscured
    registery keys  to enable stronger options. <br>
    <br>
    For ESP, I'd connect the Windows client and see what the offered
    proposals in the logs at the server side, just as you did with ike.
    You can then limit the proposals at the server end to the good ones.
    If I remember well, AES256 was an option, but esp didn't allow a DH
    group so you might need to drop that, but I could be wrong.<br>
    <br>
    Cheers,<br>
    Jafar <br>
    <br>
    <br>
    <div class="moz-cite-prefix">On 5/8/2018 1:55 PM, Houman wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CABBZOsk-9SOLJmU5k5Op2praTDJ=EP5NCOsjPMuTE+ZoFGsSow@mail.gmail.com">
      <div dir="ltr">Thank you both Christian and Jafar for the clear
        proposals.
        <div><br>
        </div>
        <div>So yes, if I wanted to support Windows 10, iOS/OSX and
          Linux with the stronger set of encryption. Do I set <b
            style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px">aes256-sha256-prfsha256-<wbr>modp2048
          </b><span
            style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px">into
            <b>ike</b> only?  Or both in <b>ike</b> and <b>esp</b>?</span></div>
        <br>
        This part wasn't quite clear to me.<br>
        <br>
        Yeah, I have already set [NegotiateDH2048_AES256] in Windows 10.
         <br>
        <br>
        Many Thanks,<br>
        Houman
        <div><span
            style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px"><br>
          </span></div>
        <div><span
            style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px"><br>
          </span></div>
        <div class="gmail_extra"><br>
          <div class="gmail_quote">On 8 May 2018 at 08:40, Christian
            Salway <span dir="ltr"><<a
                href="mailto:christian.salway@naimuri.com"
                target="_blank" moz-do-not-send="true">christian.salway@naimuri.com</a>></span>
            wrote:<br>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
              <div
                style="word-wrap:break-word;line-break:after-white-space">
                <div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">The
                    problem with Windows (10 at least) is that it offers
                    the weakest ciphers first, so you should remove sha1
                    and 3des.</div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br>
                  </div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">The
                    minimum proposals you should have and which are
                    compatible with Windows 10, OSX, IOS and Linux are
                    the following.</div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br>
                  </div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><b>proposals
                      = aes256-sha256-prfsha256-<wbr>modp2048-modp1024</b></div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br>
                  </div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">Although
                    I would recommend adding the Windows 10 registry key
                    [<span style="font-family:monospace,monospace">NegotiateDH2048_AES256</span>]
                    to use strong ciphers and then you can remove
                    MODP1024</div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br>
                  </div>
                  <div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br>
                  </div>
                  <a href="http://www.naimuri.com" target="_blank"
                    moz-do-not-send="true">
                  </a></div>
                <div><br>
                  <blockquote type="cite">
                    <div>On 7 May 2018, at 15:50, Jafar Al-Gharaibeh
                      <<a href="mailto:jafar@atcorp.com"
                        target="_blank" moz-do-not-send="true">jafar@atcorp.com</a>>
                      wrote:</div>
                    <br
                      class="gmail-m_-6903710819164957598Apple-interchange-newline">
                    <div>
                      <div bgcolor="#FFFFFF"> Houman,<br>
                        <br>
                          The Windows client proposals do not match your
                        configured proposals. Your Windows client expect
                        DG group 15 (MODP2048), where as you have:<br>
                        <br>
                        <font face="monospace, monospace">aes256-3des-sha1-modp1024<br>
                          <br>
                          change that to:<br>
                          <br>
                        </font><font face="monospace, monospace"><font
                            face="monospace, monospace">aes256-3des-sha1-modp2048</font><br>
                        </font><br>
                        I'd also add sha256 at least before sha1 (deemed
                        insecure). If you still have other clients
                        expecting modp1024, make it:<br>
                        <br>
                        <font face="monospace, monospace">aes256-3des-sha256-sha1-<wbr>modp2048-modp1024<br>
                          <br>
                          That should get you covered. <br>
                          <br>
                          Regards,<br>
                          Jafar<br>
                          <br>
                        </font>
                        <div>
                          <div class="gmail-h5"><br>
                            <div
                              class="gmail-m_-6903710819164957598moz-cite-prefix">On
                              5/7/2018 8:17 AM, Houman wrote:<br>
                            </div>
                            <blockquote type="cite">
                              <div dir="ltr">Hello,
                                <div><br>
                                </div>
                                <div>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.</div>
                                <div><br>
                                </div>
                                <div>The log on the server is:</div>
                                <div><br>
                                </div>
                                <font face="monospace, monospace">May  7
                                  12:31:06 vpn-p1 charon: 08[IKE]
                                  received proposals inacceptable<br>
                                  May  7 12:31:06 vpn-p1 charon: 08[ENC]
                                  generating IKE_SA_INIT response 0 [
                                  N(NO_PROP) ]<br>
                                  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)<br>
                                  May  7 12:32:09 vpn-p1 systemd[1]:
                                  Started Session 35 of user root.<br>
                                  May  7 12:46:21 vpn-p1 systemd[1]:
                                  Starting Cleanup of Temporary
                                  Directories...<br>
                                  May  7 12:46:21 vpn-p1
                                  systemd-tmpfiles[7016]:
                                  [/usr/lib/tmpfiles.d/var.conf:<wbr>14]
                                  Duplicate line for path "/var/log",
                                  ignoring.<br>
                                  May  7 12:46:21 vpn-p1 systemd[1]:
                                  Started Cleanup of Temporary
                                  Directories.<br>
                                  May  7 13:00:13 vpn-p1 systemd[1]:
                                  Starting Certbot...<br>
                                  May  7 13:00:13 vpn-p1 systemd[1]:
                                  Started Certbot.<br>
                                  May  7 13:08:20 vpn-p1 systemd[1]:
                                  Started Session 36 of user root.<br>
                                  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)<br>
                                  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 ]<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[IKE]
                                  received MS NT5 ISAKMPOAKLEY v9 vendor
                                  ID<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[IKE]
                                  received MS-Negotiation Discovery
                                  Capable vendor ID<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[IKE]
                                  received Vid-Initial-Contact vendor ID<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[ENC]
                                  received unknown vendor ID:
                                  01:52:8b:bb:c0:06:96:12:18:49:<wbr>ab:9a:1c:5b:2a:51:00:00:00:02<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[IKE]
                                  91.98.xxx.xxx is initiating an IKE_SA<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[CFG]
                                  received proposals:
                                  IKE:AES_CBC_256/HMAC_SHA1_96/<wbr>PRF_HMAC_SHA1/MODP_2048,
                                  IKE:AES_CBC_256/HMAC_SHA2_256_<wbr>128/PRF_HMAC_SHA2_256/MODP_<wbr>2048,
                                  IKE:AES_CBC_256/HMAC_SHA2_384_<wbr>192/PRF_HMAC_SHA2_384/MODP_<wbr>2048<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[CFG]
                                  configured proposals:
                                  IKE:AES_GCM_16_256/HMAC_SHA2_<wbr>256_128/PRF_HMAC_SHA2_256/ECP_<wbr>521,
                                  IKE:AES_CBC_256/HMAC_SHA2_256_<wbr>128/PRF_HMAC_SHA2_256/ECP_384,
                                  IKE:AES_CBC_256/3DES_CBC/HMAC_<wbr>SHA1_96/PRF_HMAC_SHA1/MODP_<wbr>1024<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[IKE]
                                  remote host is behind NAT<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[IKE]
                                  received proposals inacceptable<br>
                                  May  7 13:11:27 vpn-p1 charon: 12[ENC]
                                  generating IKE_SA_INIT response 0 [
                                  N(NO_PROP) ]<br>
                                  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)<br>
                                  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)<br>
                                  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 ]<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[IKE]
                                  received MS NT5 ISAKMPOAKLEY v9 vendor
                                  ID<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[IKE]
                                  received MS-Negotiation Discovery
                                  Capable vendor ID<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[IKE]
                                  received Vid-Initial-Contact vendor ID<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[ENC]
                                  received unknown vendor ID:
                                  01:52:8b:bb:c0:06:96:12:18:49:<wbr>ab:9a:1c:5b:2a:51:00:00:00:02<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[IKE]
                                  91.98.xxx.xxx is initiating an IKE_SA<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[CFG]
                                  received proposals:
                                  IKE:AES_CBC_256/HMAC_SHA1_96/<wbr>PRF_HMAC_SHA1/MODP_2048,
                                  IKE:AES_CBC_256/HMAC_SHA2_256_<wbr>128/PRF_HMAC_SHA2_256/MODP_<wbr>2048,
                                  IKE:AES_CBC_256/HMAC_SHA2_384_<wbr>192/PRF_HMAC_SHA2_384/MODP_<wbr>2048<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[CFG]
                                  configured proposals:
                                  IKE:AES_GCM_16_256/HMAC_SHA2_<wbr>256_128/PRF_HMAC_SHA2_256/ECP_<wbr>521,
                                  IKE:AES_CBC_256/HMAC_SHA2_256_<wbr>128/PRF_HMAC_SHA2_256/ECP_384,
                                  IKE:AES_CBC_256/3DES_CBC/HMAC_<wbr>SHA1_96/PRF_HMAC_SHA1/MODP_<wbr>1024<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[IKE]
                                  remote host is behind NAT<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[IKE]
                                  received proposals inacceptable<br>
                                  May  7 13:11:28 vpn-p1 charon: 16[ENC]
                                  generating IKE_SA_INIT response 0 [
                                  N(NO_PROP) ]<br>
                                  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)</font>
                                <div><br>
                                </div>
                                <div>The Server's ipsec.conf is:</div>
                                <div><br>
                                </div>
                                <div>
                                  <div><font face="monospace, monospace">config
                                      setup</font></div>
                                  <div><font face="monospace, monospace"> 
                                      strictcrlpolicy=yes</font></div>
                                  <div><font face="monospace, monospace"> 
                                      uniqueids=never</font></div>
                                  <div><font face="monospace, monospace">conn
                                      roadwarrior</font></div>
                                  <div><font face="monospace, monospace"> 
                                      auto=add</font></div>
                                  <div><font face="monospace, monospace"> 
                                      compress=no</font></div>
                                  <div><font face="monospace, monospace"> 
                                      type=tunnel</font></div>
                                  <div><font face="monospace, monospace"> 
                                      keyexchange=ikev2</font></div>
                                  <div><font face="monospace, monospace"> 
                                      fragmentation=yes</font></div>
                                  <div><font face="monospace, monospace"> 
                                      forceencaps=yes</font></div>
                                  <div><font face="monospace, monospace"> 
                                      ike=aes256gcm16-sha256-ecp521,<wbr>aes256-sha256-ecp384,aes256-<wbr>3des-sha1-modp1024!</font></div>
                                  <div><font face="monospace, monospace"> 
                                      esp=aes256gcm16-sha256,aes256-<wbr>3des-sha256-sha1!</font></div>
                                  <div><font face="monospace, monospace"> 
                                      dpdaction=clear</font></div>
                                  <div><font face="monospace, monospace"> 
                                      dpddelay=180s</font></div>
                                  <div><font face="monospace, monospace"> 
                                      rekey=no</font></div>
                                  <div><font face="monospace, monospace"> 
                                      left=%any</font></div>
                                  <div><font face="monospace, monospace"> 
                                      leftid=@${VPNHOST}</font></div>
                                  <div><font face="monospace, monospace"> 
                                      leftcert=cert.pem</font></div>
                                  <div><font face="monospace, monospace"> 
                                      leftsendcert=always</font></div>
                                  <div><font face="monospace, monospace"> 
                                      leftsubnet=<a
                                        href="http://0.0.0.0/0"
                                        target="_blank"
                                        moz-do-not-send="true">0.0.0.0/0</a></font></div>
                                  <div><font face="monospace, monospace"> 
                                      right=%any</font></div>
                                  <div><font face="monospace, monospace"> 
                                      rightid=%any</font></div>
                                  <div><font face="monospace, monospace"> 
                                      rightauth=eap-radius</font></div>
                                  <div><font face="monospace, monospace"> 
                                      eap_identity=%any</font></div>
                                  <div><font face="monospace, monospace"> 
                                      rightdns=208.67.222.222,208.<wbr>67.220.220</font></div>
                                  <div><font face="monospace, monospace"> 
                                      rightsourceip=${VPNIPPOOL}</font></div>
                                  <div><font face="monospace, monospace"> 
                                      rightsendcert=never</font></div>
                                </div>
                                <div><br>
                                </div>
                                <div>Have the supported ike/esp
                                  proposals somehow been changed
                                  recently after a recent Windows 10
                                  update?</div>
                                <div><br>
                                </div>
                                <div>I have made these changes on the
                                  Windows 10, after googling for a
                                  solution:</div>
                                <div><br>
                                </div>
                                <div><font face="monospace, monospace">-
                                    The firewall on Windows 10 is
                                    currently disabled.  </font></div>
                                <font face="monospace, monospace">- I
                                  have set NegotiateDH2048_AES256 = 1 in
                                  Regedit<br>
                                  - AssumeUDPEncapsulationContextO<wbr>nSendRule
                                  = 2 in Regedit</font>
                                <div><br>
                                </div>
                                <div>I can't think of anything else I
                                  could do on the Windows 10 client.<br>
                                  <div><br>
                                  </div>
                                  <div>According to my notes, these are
                                    the proposed protocols for Windows
                                    10:</div>
                                  <div><br>
                                  </div>
                                  <div>
                                    <div><font face="monospace,
                                        monospace"># these ike and esp
                                        settings are tested on Mac
                                        10.12, iOS 10 and Windows 10</font></div>
                                    <div><font face="monospace,
                                        monospace"># iOS/Mac with
                                        appropriate configuration
                                        profiles use
                                        AES_GCM_16_256/PRF_HMAC_SHA2_<wbr>256/ECP_521</font></div>
                                    <div><font face="monospace,
                                        monospace"># Windows 10 uses
                                        AES_CBC_256/HMAC_SHA2_256_128/<wbr>PRF_HMAC_SHA2_256/ECP_384</font></div>
                                  </div>
                                  <div><br>
                                  </div>
                                  <div>Is there a website that
                                    translates
                                    AES_CBC_256/HMAC_SHA2_256_128/<wbr>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.</div>
                                  <div><br>
                                  </div>
                                  <div>If you have any other advice,
                                    please help me.</div>
                                  <div><br>
                                  </div>
                                  <div>Many Thanks,</div>
                                  <div><br>
                                  </div>
                                  <div><br>
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                                  <div><br>
                                  </div>
                                  <div><br>
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