DHCP Relay Advice



  • Hello,

    Trying to setup a simple pfsense box.  Currently has 3 interfaces, wan, lan, opt1.

    OPT1 goes to a Windows server which will be hosting active directory, dhcp, dns… all network services basically.  LAN goes to a switch, which then goes out to all the other computers.  T1 line is connected to WAN.

    The ideal setup would be having the Windows server on OPT1 and have the LAN pass DHCP requests onto the OPT1 interface.  So far this has deemed unsuccessful.

    Current setup:
    WAN is a static IP to the Internet.
    LAN 192.168.1.1
    OPT1 192.168.2.1

    Rules are setup to allow any/all traffic from OPT1 and LAN.  Additionally I have temporarily setup a PPTP VPN on 192.168.1.2 (192.168.1.16/28), this is just so I can access everything remotely without having to open a bunch of ports for now.

    The Windows server has an IP address of 192.168.2.2, and currently being forwarded DHCP requests from the LAN.  However clients are unable to obtain an IP.  The network on the Windows server is 10.0.100.1 (though this shouldn't matter, right?).

    Can you please advise me if I'm doing this correctly?  At the moment no clients are able to connect to the network.



  • As long as you have multiple scopes with the appropriate IP ranges on the Windows server, putting in its IP as the relay will do just what you're looking for. That's how I do DHCP on several networks.



  • Ok, so basically I would need a scope for 192.168.2.1?  I suppose it would be easier to change my OPT1 interface to 10.0.100.1 since thats the scope we already have setup.  Sound right?



  • You'll need one scope per interface, each interface has to have its own subnet. Then the DHCP relay tags the forward with the subnet of that interface, and Windows knows which scope to serve from there.



  • Ah yes, worked perfectly after wrestling with it.  Changed the LAN interface to match the IP address of scope on Windows, after a little more config of scope options it was working like a charm.

    My PPTP VPN quit working though, any idea how I could make that work again with this configuration? Or should I just forget about it..



  • I can't think of anything to do with DHCP relay that would affect PPTP. Start a new thread describing that issue.



  • The VPN randomly started working.  I'm not gong to ask any questions and just go along with it  ;D

    Thanks again for all your help.


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