About OpenVpn

About OpenVPN SERVER

If you want to install the SERVER part of OpenVPN on windows 10 see https://shebangthedolphins.net/vpn_openvpn_windows_server.html

About OpenVPN CLIENT

Hardware requirements

As a rule of thumb you need 20MHz/Mbps of traffic on a CPU with AES-NI chipset. You must of course add the traffic from both directions. If your CPU does not have AES-NI, double this number.

You should start out with 1GB + 5...10MB/user. So for 1000 connected users that would be 6GB...11GB of memory. Memory requirements are highly dependent on the amount of connected devices, and how much NAT traffic you’re doing.

Command line usage from Windows

cd 'C:\Users\User\Desktop\mazars\' 
cmd /c "C:\program files\OpenVPN\bin\openvpn.exe" --config .\mazars-support.ovpn

Multiple OpenVPN connections from Windows

You need one TAP adapter per connection.

New way to create an extra TAP-ADAPTER from an admin PowerShell

cd "C:\Program Files\OpenVPN\bin\"
# create a few TAP adapters (run as many times as you need)
.\tapctl.exe create
.\tapctl.exe create
.\tapctl.exe create

OLD WAY to create an extra TAP-ADAPTER

From admin CMD shell:

cd "C:\Program Files\TAP-Windows\bin" 
.\addtap.bat

Troubleshooting

Error "Connecting to management interface failed."

---

OpenVPN GUI
---------------------------
Connecting to management interface failed.
View log file (C:\Users\user\OpenVPN\log\Doculand.log) for more details.

FIX: Just restart these services: OpenVPNService, OpenVPNServiceInteractive

Get-Service -name 'OpenVPNService*' | ?{$_.name -ne 'OpenVPNServiceLegacy'} | Restart-service

How to start VPN from the command line (π.χ. αν δεν σας ξεκινά το openvpn-gui)

Σε ένα admin powershell:

cd 'C:\Program Files\OpenVPN\config\' # ο φάκελος που έχετε τo .ovpn αρχείο

& "C:\Program Files\OpenVPN\bin\openvpn.exe" --config lala.ovpn # το file name του .ovpn αρχείου

Windows client gets this error: "route gateway is not reachable on any active network adapters"

Method 1 (BEST)

Admin PowerShell

cd "C:\Program Files\OpenVPN\bin\"
# delete all TAP adapters
((.\tapctl.exe list) -replace '\t.*','') | %{ .\tapctl delete "$_"}
# create a few TAP adapters (run as many times as you need)
.\tapctl.exe create
.\tapctl.exe create
.\tapctl.exe create
.\tapctl.exe list

Method 2 (old OpenVPN)

# FROM ADMINISTRATIVE POWERSHELL
& "C:\Program Files\TAP-Windows\bin\deltapall.bat"
& "C:\Program Files\TAP-Windows\bin\addtap.bat"
# ^--REPEAT IF YOU NEED MORE THAN 1 TAP ADAPTERS (N tap adapters allow for N concurrent VPNs)

Method 2 (may lock you out if you are remote and doesn't always work)

# FROM ADMINISTRATIVE POWERSHELL
netsh dump
netsh winsock reset
netsh int ip reset resetlog.txt
ipconfig /flushdns
# CAUTION: THIS WILL TEMPORARILY DROP ALL NETWORK CONNECTIONS 
# AND IF USING DHCP IT WILL ALSO REFRESH THE IP 
Get-NetAdapter | Disable-NetAdapter -Confirm:$False; Get-NetAdapter | Enable-NetAdapter; ipconfig /renew

If the above don't work, reboot the client's PC.

Method 3 (not tested):

Add the following lines to the bottom of the OpenVPN configuration file on the client:

tap-sleep 3
verb 4
route-delay 1 3
route-method exe
ip-win32 netsh