Hi, I've been bothered by this for long and did many research and experiments but couldn't solve it, so I have to ask.. I'm running OpenConnect server 0.10.6 on CentOS 7, and AnyConnect 4.x on iPhone 5 I use certificates authentication, and everything worked well, on iPhone I can do a single click and I'm connected, I'm happy. When I put my iPhone into sleep mode, in some seconds or a minute, the connection between iPhone and the server is dropped with error message in /var/log/messages "worker[0.9.2342.19200300.100.1.1]: 120.42.4.168 worker-vpn.c:1048: GnuTLS error (at worker-vpn.c:1048): The TLS connection was non-properly terminated." and "too short UDP packet" This is fine. I expect that, because it is in sleep mode and if I wake up my iPhone manually, it will get reconnected automatically, so this is not a problem. BUT, the problem is, even if I do NOT wake up my phone, I still find iPhone will connect to the server automatically very often. By very often I mean the reconnection will happen almost every minute or every two minutes, sometimes even just a few seconds after the connection was dropped. Then the connection will dropped again in a minute or so, then it will reconnect again in a minute or so. This all happened when iPhone is in sleep mode. When the reconnection happens, I can find 1) in /var/log/message, there is 'ocserv[21763]: worker: tlslib.c:378: no certificate was found' printed. I don't know why, because I'm using certificate authentication well. 2) I can confirm the reconnection happens because there is 'vpns0' created when I do a 'ifconfig' 3) Again, the iPhone is in sleep mode, it was not wake up manually or by any iOS notification. In /etc/ocserv/ocserv.conf, I have below settings keepalive = 324000 dpd = 90 mobile-dpd = 3600 Because I set mobile-dpd to be an hour, so I do not expect iPhone to be waken up by the server such frequently. I only expect the server to wake up iPhone with a dpd message every hour so iPhone will only reconnect every hour once in sleep mode. I would appreciate any hints to the problem, and let me know if you need any more info. This is a big problem to me, because if I leave my iPhone in sleep for a night, the reconnection will happen more than a hundred times, so I appreciate your help to troubleshoot this! PS, other configuration options in ocserv.conf, not sure if they can be of any help tcp-port = 3306 udp-port = 3306 isolate-workers = true try-mtu-discovery = false cookie-timeout = 324000 cisco-client-compat = true