It seems 7.08 still has the same issue in my case. Any suggestions? G. ./configure --with-vpnc-script=/usr/share/vpnc-scripts/vpnc-script BUILD OPTIONS: SSL library: OpenSSL PKCS#11 support: no DTLS support: yes ESP support: yes libproxy support: no RSA SecurID support: no PSKC OATH file support: no GSSAPI support: no Yubikey support: no LZ4 compression: no Java bindings: no Build docs: no Unit tests: no make check ... PASS: lzstest PASS: seqtest FAIL: bad_dtls_test ============================================================================ Testsuite summary for openconnect 7.08 ============================================================================ # TOTAL: 3 # PASS: 2 # SKIP: 0 # XFAIL: 0 # FAIL: 1 # XPASS: 0 # ERROR: 0 With -vv ping -c1 -W 2 -s 1394 host.tld - succeeds Sent ESP packet of 116 bytes No work to do; sleeping for 10000 ms... Received ESP packet of 132 bytes No work to do; sleeping for 15000 ms... Sent ESP packet of 1444 bytes Sent ESP packet of 84 bytes No work to do; sleeping for 15000 ms... Received ESP packet of 1460 bytes No work to do; sleeping for 15000 ms... Sent ESP packet of 116 bytes No work to do; sleeping for 15000 ms... Received ESP packet of 164 bytes No work to do; sleeping for 15000 ms... ping -c1 -W 2 -s 1395 host.tld - fails Sent ESP packet of 116 bytes No work to do; sleeping for 4000 ms... Received ESP packet of 132 bytes No work to do; sleeping for 15000 ms... Sent ESP packet of 1444 bytes Sent ESP packet of 100 bytes No work to do; sleeping for 15000 ms... Received ESP packet of 1460 bytes Received ESP packet with invalid HMAC No work to do; sleeping for 15000 ms... ifconfig tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:10.150.4.56 P-t-P:10.150.4.56 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1400 Metric:1 RX packets:120 errors:0 dropped:0 overruns:0 frame:0 TX packets:135 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:23520 (23.5 KB) TX bytes:22269 (22.2 KB) I also have some Wireshark captures showing "malformed packet" when trying to open an RDP connection using Remmina.