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Win 10 Firewall Preventing Connection to OpenVPN Server

Posted: Thu Jun 04, 2020 6:32 am
by jsingleton
Not sure if this is the right place to post as my issue probably has more to do with Windows Firewall than with OpenVPN. Any help would be appreciated, even if it's just telling me a better place to post my question.

I have an OpenVPN server configured on my Asus router. On my Windows 10 laptop I have OpenVPN GUI. In the past I have been able to connect without any issues. However, after recently installing a Windows Feature Update, I can no longer connect unless I disable my Windows Firewall (client side). Unfortunately the Windows Firewall Log does not show anything being blocked during my failed connection attempts.

Here is the OpenVPN log file for when Windows Firewall is on and I am unable to connect to the server:

Code: Select all

Wed Jun 03 23:07:32 2020 OpenVPN 2.4.9 x86_64-w64-mingw32 [SSL (OpenSSL)] [LZO] [LZ4] [PKCS11] [AEAD] built on Apr 16 2020
Wed Jun 03 23:07:32 2020 Windows version 6.2 (Windows 8 or greater) 64bit
Wed Jun 03 23:07:32 2020 library versions: OpenSSL 1.1.1f  31 Mar 2020, LZO 2.10
Enter Management Password:
Wed Jun 03 23:07:34 2020 WARNING: --ns-cert-type is DEPRECATED.  Use --remote-cert-tls instead.
Wed Jun 03 23:07:34 2020 TCP/UDP: Preserving recently used remote address: [AF_INET]<serverIPRedacted>:1194
Wed Jun 03 23:07:34 2020 UDP link local: (not bound)
Wed Jun 03 23:07:34 2020 UDP link remote: [AF_INET]<serverIPRedacted>:1194
Wed Jun 03 23:08:34 2020 [UNDEF] Inactivity timeout (--ping-restart), restarting
Wed Jun 03 23:08:34 2020 SIGUSR1[soft,ping-restart] received, process restarting
Wed Jun 03 23:08:39 2020 WARNING: --ns-cert-type is DEPRECATED.  Use --remote-cert-tls instead.
Wed Jun 03 23:08:39 2020 TCP/UDP: Preserving recently used remote address: [AF_INET]<serverIPRedacted>:1194
Wed Jun 03 23:08:39 2020 UDP link local: (not bound)
Wed Jun 03 23:08:39 2020 UDP link remote: [AF_INET]<serverIPRedacted>:1194
Any help would be appreciated. Thanks in advance.

Re: Win 10 Firewall Preventing Connection to OpenVPN Server

Posted: Thu Jun 04, 2020 12:37 pm
by TinCanTech
This sounds more like either:
  • You edited your Windows Firewall and forgot what you did.
  • Or the Server IP is a non-routable IP (Not a public IP) and you are on a different LAN.
Windows Firewall normally allows egress to all (at least most) outgoing traffic otherwise
we would have thousands of people claiming a Windows Update broke their VPN ..

Or your server firewall is blocking you.

Re: Win 10 Firewall Preventing Connection to OpenVPN Server

Posted: Fri Jun 05, 2020 6:52 am
by jsingleton
@TinCanTech Thanks for the reply. You were correct, I had indeed made a rule in my Windows Firewall that I had forgotten about (the rule was to allow outbound connection for openvpn.exe if it was "secure", so I guess it wasn't technically blocking anything and that's why there was no related message for that in the Windows Firewall Log). I deleted that rule and am now able to connect. Thanks!