VLAN OpenVPN issues



  • Good Morning,

    I've just rebuilt my network to include VLANs, mainly to learn, with the end result being of isolating all of my IoT devices.

    So far I think I've muddled through enough guides to gain a reasonable idea of what I am doing. I am however stumped one one thing (so far).

    When I am on the WiFi (and therefore VLAN 10) I can get internet etc etc and do everything I expect. Except, when I try and connect OpenVPN to a different pfSense box.
    I've had this second box up and working for years, with an OpenVPN server. When I am not on my internet I can connect and I have full internet access and access to the LAN
    When I connect from inside the VLAN however the connection completes, I get issued an IP address. But I can't access the internet or the LAN. Everything just times out.
    I am guessing it is a routing issue to do with my VLANs, but not sure where to start

    Kind Regards


  • LAYER 8 Global Moderator

    And this other vpn server your connecting too... What is the tunnel network used? Does it overlap your new vlan network? What is this remote network your trying to access does it overlap your new vlan 10 network?



  • If I understand the question correctly (and please excuse me if I dont) I think you might have hit the nail on the head.

    VLAN 10 is a network of 192.168.10.0/24... and now I think about ti when you connect to the tunnel you are issued a 192.168.10.x address. Will this give me the issues I am having?


  • LAYER 8 Global Moderator

    You can not have tunnel network or remote network that overlaps your current network.

    If your on 192.168.10.0/24 and the tunnel network is the same? Or overlaps say 192.168.0.0/16 or the remote network again is the same as your local or overlaps... Then yeah your going to have a bad day ;)



  • @johnpoz
    Amazing, thank you. Makes complete sense but one of those things I was chasing my own tail on. Moved the tunnel network to 192.168.3.0/24. And unsurprisingly it now connects fine on the VLAN and works as intended.


  • LAYER 8 Global Moderator

    Good to hear - yeah this is why its a good idea to use non common networks for tunnel and your local networks.. For example 192.168.0 and 192.168.1 are very common!

    Good tunnel networks are in the 17.16/12 rfc1918 space... Like say 172.29.14/24 or something ;)

    Many hot spots that you might be at where you want to go home so using common networks locally.. Can cause you problems from your remote location when your wanting to vpn home... So good to use odd networks at home too.. I use 192.168.9/24 for my normal lan, have yet to run into an issue with that.. But yeah you never know what network you might be on ;)

    Also why good to not use large networks.. When you see someone using 192.168/16 or 10/8 they prob going to have issues trying to vpn out or in ;)


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