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    <p>P.P.S.</p>
    <p>I apologize for the table was garbled by Thunderbird, so I will
      repost it as a snip:</p>
    <p><img src="cid:part1.TDEB4uqG.uQBwD09c@alu.hr" alt=""></p>
    <p>Sorry for the inconvenience.</p>
    <p>Kind regards,<br>
      Mirsad Todorovac<br>
    </p>
    <div class="moz-cite-prefix">On 1/14/2022 9:21 AM, Mirsad Goran
      Todorovac wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:e3f73e40-1006-e326-4cd8-24acb25f3928@alu.hr">P.S.
      <br>
      <br>
      I am testing the stuff more thoroughly for interoperability. :-)
      <br>
      <br>
      Apparently, it works like this compatibility matrix:
      <br>
      <br>
                             L2TP win 10  L2TP Android  IKEv2 win10 
      IKEv2 Android  multiple  multiple
      <br>
                             connect      connect       connect
      connect        L2TP      IKEv2
      <br>
      <br>
      4.5 USE_DH2=true       + +             +            +             
      +         -
      <br>
      4.5 USE_DH2=false      not tested
      <br>
      4.6 USE_DH2=true       +            +             + +             
      +         -
      <br>
      4.6 USE_DH2=false      +            -             + +             
      +         -
      <br>
      <br>
      Android includes testing both on Samsung Galaxy A22 5G phone and
      Tab S6 Lite tablet.
      <br>
      <br>
      Apparently, concurrent 4.5 USE_DH2=true or IKEv2 doesn't work
      either, so I may have to revert the settings from our accountant
      to L2TP connection, despite being slower, for it seems awkward
      that I might preempt his accounting session while testing the
      stuff.
      <br>
      <br>
      It seemed that I have a bit rushed things with the upgrade to
      IKEv2, thinking that it will be safe just as L2TP setup?
      <br>
      Is there something I'm doing wrong in the ikev2.conf below, or is
      it a bug in libreswan? It seems unlikely that such behavior was
      left unnoticed until now, but at least it appears that it is not a
      regression in 4.6 compared to 4.5. :-/
      <br>
      <br>
      I hope this helps, and I am hoping there is a workaround or fix.
      <br>
      (I am currently testing concurrent L2TP from 3 devices for several
      hours ...).
      <br>
      <br>
      Kind regards,
      <br>
      Mirsad Todorovac
      <br>
      <br>
      On 1/14/2022 7:08 AM, Mirsad Goran Todorovac wrote:
      <br>
      <blockquote type="cite">Hello,
        <br>
        <br>
        I can confirm that the IKEv2 connection was alive for the entire
        night of testing:
        <br>
        <br>
        000 #80: "MYCONN-ikev2-cp"[2] 94.253.210.164:4500
        STATE_V2_ESTABLISHED_IKE_SA (established IKE SA); EXPIRE in
        27522s; newest; idle;
        <br>
        000 #81: "MYCONN-ikev2-cp"[2] 94.253.210.164:4500
        STATE_V2_ESTABLISHED_CHILD_SA (established Child SA); LIVENESS
        in 6s; EXPIRE in 28536s; newest; eroute owner; IKE SA #80; idle;
        <br>
        000 #81: "MYCONN-ikev2-cp"[2] 94.253.210.164
        <a class="moz-txt-link-abbreviated" href="mailto:esp.a8ff51a4@94.253.210.164">esp.a8ff51a4@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:esp.303eb9bd@161.53.235.3">esp.303eb9bd@161.53.235.3</a>
        <a class="moz-txt-link-abbreviated" href="mailto:tun.0@94.253.210.164">tun.0@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:tun.0@161.53.235.3">tun.0@161.53.235.3</a> Traffic: ESPin=1MB
        ESPout=41MB ESPmax=0B
        <br>
        <br>
        Less than 10 seconds from initiating IKEv2 connection from the
        Android tablet (Samsung Galaxy Tab S6 Lite), the connection was
        severed. But both ends still think it is connected:
        <br>
        <br>
        000 #80: "MYCONN-ikev2-cp"[2] 94.253.210.164:4500
        STATE_V2_ESTABLISHED_IKE_SA (established IKE SA); EXPIRE in
        27299s; idle;
        <br>
        000 #81: "MYCONN-ikev2-cp"[2] 94.253.210.164:4500
        STATE_V2_ESTABLISHED_CHILD_SA (established Child SA); EXPIRE in
        28313s; IKE SA #80; idle;
        <br>
        000 #81: "MYCONN-ikev2-cp"[2] 94.253.210.164
        <a class="moz-txt-link-abbreviated" href="mailto:esp.a8ff51a4@94.253.210.164">esp.a8ff51a4@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:esp.303eb9bd@161.53.235.3">esp.303eb9bd@161.53.235.3</a>
        <a class="moz-txt-link-abbreviated" href="mailto:tun.0@94.253.210.164">tun.0@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:tun.0@161.53.235.3">tun.0@161.53.235.3</a> Traffic: ESPin=2MB
        ESPout=105MB ESPmax=0B
        <br>
        000 #83: "MYCONN-ikev2-cp"[2] 94.253.210.164:46855
        STATE_V2_ESTABLISHED_IKE_SA (established IKE SA); EXPIRE in
        28745s; newest; idle;
        <br>
        000 #84: "MYCONN-ikev2-cp"[2] 94.253.210.164:46855
        STATE_V2_ESTABLISHED_CHILD_SA (established Child SA); LIVENESS
        in 5s; EXPIRE in 28745s; newest; eroute owner; IKE SA #83; idle;
        <br>
        000 #84: "MYCONN-ikev2-cp"[2] 94.253.210.164
        <a class="moz-txt-link-abbreviated" href="mailto:esp.cf38d849@94.253.210.164">esp.cf38d849@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:esp.476cc068@161.53.235.3">esp.476cc068@161.53.235.3</a>
        <a class="moz-txt-link-abbreviated" href="mailto:tun.0@94.253.210.164">tun.0@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:tun.0@161.53.235.3">tun.0@161.53.235.3</a> Traffic: ESPin=145KB
        ESPout=10MB ESPmax=0B
        <br>
        <br>
        Now I tested ping 8.8.8.8 and it is also down, while
        whatismyipaddress.com shows that the Android tablet is
        connected. :-/
        <br>
        <br>
        The session log is here (only the interesting event, not the
        entire night of testing):
        <a class="moz-txt-link-freetext" href="https://domac.alu.hr/mtodorov/ikev2-20220113-03.log">https://domac.alu.hr/mtodorov/ikev2-20220113-03.log</a>
        <br>
        <br>
        After I reconnected Windows 10, the Android device appears
        kicked out ...
        <br>
        <br>
        But it isn't shown in `ipsec showstates`, as it still believes
        it has connection on both devices:
        <br>
        <br>
        000 #83: "MYCONN-ikev2-cp"[2] 94.253.210.164:46855
        STATE_V2_ESTABLISHED_IKE_SA (established IKE SA); EXPIRE in
        28290s; idle;
        <br>
        000 #84: "MYCONN-ikev2-cp"[2] 94.253.210.164:46855
        STATE_V2_ESTABLISHED_CHILD_SA (established Child SA); EXPIRE in
        28290s; IKE SA #83; idle;
        <br>
        000 #84: "MYCONN-ikev2-cp"[2] 94.253.210.164
        <a class="moz-txt-link-abbreviated" href="mailto:esp.cf38d849@94.253.210.164">esp.cf38d849@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:esp.476cc068@161.53.235.3">esp.476cc068@161.53.235.3</a>
        <a class="moz-txt-link-abbreviated" href="mailto:tun.0@94.253.210.164">tun.0@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:tun.0@161.53.235.3">tun.0@161.53.235.3</a> Traffic: ESPin=864KB
        ESPout=12MB ESPmax=0B
        <br>
        000 #86: "MYCONN-ikev2-cp"[2] 94.253.210.164:4500
        STATE_V2_ESTABLISHED_IKE_SA (established IKE SA); EXPIRE in
        28667s; newest; idle;
        <br>
        000 #87: "MYCONN-ikev2-cp"[2] 94.253.210.164:4500
        STATE_V2_ESTABLISHED_CHILD_SA (established Child SA); LIVENESS
        in 17s; EXPIRE in 28667s; newest; eroute owner; IKE SA #86;
        idle;
        <br>
        000 #87: "MYCONN-ikev2-cp"[2] 94.253.210.164
        <a class="moz-txt-link-abbreviated" href="mailto:esp.2dcf960@94.253.210.164">esp.2dcf960@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:esp.ea55d21d@161.53.235.3">esp.ea55d21d@161.53.235.3</a>
        <a class="moz-txt-link-abbreviated" href="mailto:tun.0@94.253.210.164">tun.0@94.253.210.164</a> <a class="moz-txt-link-abbreviated" href="mailto:tun.0@161.53.235.3">tun.0@161.53.235.3</a> Traffic: ESPin=2MB
        ESPout=9MB ESPmax=0B
        <br>
        <br>
        On average, we will have only one user on the VPN for the most
        times, but two accountants could accidentally kick out each
        other, couldn't they?
        <br>
        <br>
        I hope any of this helps.
        <br>
        <br>
        BTW, Android L2TP connection tested with 4.5 USE_DH2=true did
        not connect from Android, while it did from Windows 10. I would
        like to have them all running stable and symmetrically.
        <br>
        <br>
        Kind regards,
        <br>
        Mirsad Todorovac
        <br>
        <br>
        On 1/13/2022 11:36 PM, Mirsad Goran Todorovac wrote:
        <br>
        <blockquote type="cite">Hello,
          <br>
          <br>
          I tried to summarize in the title, and so far I have been able
          to associate the teardown of Windows 10 data stream with a
          simultaneous IKEv2 connection that came during the test signal
          (live TV stream) from an Android tablet on our test Linux
          server.
          <br>
          <br>
          The Windows laptop had no realtime stream and neither DNS
          resolution. I did not check ping, but I suspect it wouldn't
          pass either by the symptoms.
          <br>
          <br>
          This time I compiled without the USE_DH2=true and used it with
          ms-dh-downgrade=true.
          <br>
          <br>
          conn MYCONN-ikev2-cp
          <br>
                  # The server's actual IP goes here - not elastic IPs
          <br>
                  left=161.53.235.3
          <br>
                  leftcert=vpn.alu.hr
          <br>
                  <a class="moz-txt-link-abbreviated" href="mailto:leftid=@vpn.alu.hr">leftid=@vpn.alu.hr</a>
          <br>
                  leftsendcert=always
          <br>
                  leftsubnet=0.0.0.0/0
          <br>
                  leftrsasigkey=%cert
          <br>
                  # Clients
          <br>
                  right=%any
          <br>
                  # your addresspool to use - you might need NAT rules
          if providing full internet to clients
          <br>
                  rightaddresspool=192.168.101.10-192.168.101.253
          <br>
                  # optional rightid with restrictions
          <br>
                  rightid="O=ALU-UNIZG,CN=win7client.alu.hr"
          <br>
                  rightca=%same
          <br>
                  rightrsasigkey=%cert
          <br>
                  #
          <br>
                  # connection configuration
          <br>
                  # DNS servers for clients to use
          <br>
                  modecfgdns=8.8.8.8,192.168.100.1
          <br>
                  # Versions up to 3.22 used modecfgdns1 and modecfgdns2
          <br>
                  #modecfgdns1=8.8.8.8
          <br>
                  #modecfgdns2=193.110.157.123
          <br>
                  narrowing=yes
          <br>
                  # recommended dpd/liveness to cleanup vanished clients
          <br>
                  dpddelay=30
          <br>
                  dpdtimeout=120
          <br>
                  dpdaction=clear
          <br>
                  auto=add
          <br>
                  ikev2=insist
          <br>
                  rekey=no
          <br>
esp=aes_gcm256,aes_gcm128,aes256-sha2_512,aes128-sha2_512,aes256-sha1,aes128-sha1
          <br>
                  #
esp=aes_gcm256-null,aes_gcm128-null,aes256-sha2_512,aes128-sha2_512,aes256-sha1,aes128-sha1,aes_gcm256-null;modp1024<br>
                  # ikev2 fragmentation support requires libreswan 3.14
          or newer
          <br>
                  fragmentation=yes
          <br>
                  # optional PAM username verification (eg to implement
          bandwidth quota
          <br>
                  # pam-authorize=yes
          <br>
                  ms-dh-downgrade=yes
          <br>
                  authby=rsa-sha1
          <br>
          <br>
          Both the `ipsec showstates` and Windows 10 did not reflect
          that the data stream was interrupted, and eithe had Android.
          <br>
          <br>
          Here is the session log 1 and log2.
          <br>
          The interesting part is probably close to the end of both
          logs.
          <br>
          <br>
          [1] <a class="moz-txt-link-freetext" href="https://domac.alu.hr/mtodorov/ikev2-20220113-01.log">https://domac.alu.hr/mtodorov/ikev2-20220113-01.log</a>
          <br>
          [2] <a class="moz-txt-link-freetext" href="https://domac.alu.hr/mtodorov/ikev2-20220113-02.log">https://domac.alu.hr/mtodorov/ikev2-20220113-02.log</a>
          <br>
          <br>
          I will supply more information as I am testing. I wonder if
          this is related to removal of USE_DH2=true from the
          compilation or will the connection be stable unless there is
          an interference from another (Android) client. The Android had
          also lost connectivity, though the wizard said "Connected".
          <br>
          <br>
          Hope this helps. I would have to revert to 4.5 and
          USE_DH2=true and I don't think it would be prudent to move it
          to the production VPN until we resolve such issues :-/
          <br>
          <br>
          The accountant guy would think I'm incompetent if his VPN
          connection breaks in the middle of accounting salaries :-(
          <br>
          <br>
          Any idea?
          <br>
          <br>
          Kind regards,
          <br>
          Mirsad
          <br>
          <br>
          -- <br>
          Mirsad Goran Todorovac
          <br>
          CARNet sistem inženjer
          <br>
          Grafički fakultet | Akademija likovnih umjetnosti
          <br>
          Sveučilište u Zagrebu
          <br>
        </blockquote>
        <br>
        -- <br>
        Mirsad Goran Todorovac
        <br>
        CARNet sistem inženjer
        <br>
        Grafički fakultet | Akademija likovnih umjetnosti
        <br>
        Sveučilište u Zagrebu
        <br>
      </blockquote>
      <br>
    </blockquote>
    <pre class="moz-signature" cols="72">-- 
Mirsad Goran Todorovac
CARNet sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
--
CARNet system engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
tel. +385 (0)1 3711 451
mob. +385 91 57 88 355</pre>
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