DHCP relay issue



  • Hey guys, im trying to set up a network here with the pfsense server working with my dhcp server that already exists. I already tried using the dhcp relay for my LAN but it didnt work. Initially it works well when i test with the default ip in LAN but when i enable the dhcp relay to get the ip from my dhcp server it stops working.

    Something like that:

    Internet -> DHCP Server -> Pfsense Server -> Switch …

    There is any additional changes that i gotta do instead of only enable the dhcp relay on pfsense?


  • Rebel Alliance Global Moderator

    So your dhcp server is on the wan side of your pfsense?  Normally you would use the dhcp relay to relay from multiple segments on your lan side to use dhcp server on one of your lan segments.  If on wan side I would assume your natting, this could be an issue.



  • @johnpoz:

    So your dhcp server is on the wan side of your pfsense?  Normally you would use the dhcp relay to relay from multiple segments on your lan side to use dhcp server on one of your lan segments.  If on wan side I would assume your natting, this could be an issue.

    Thanks for reply.

    Yes, its on the wan side of pfsense server, is it an issue? I mean, there is any way to set up that natting im suggesting?


  • Rebel Alliance Global Moderator

    Well yeah, I can't think of why you would ever set it up like that to be honest.  By default pfsense would be natting traffic from lan to wan.  Did you turn off natting and just using as firewall and router?

    What are you wanting to accomplish with pfsense in your setup, if your networks dchp server is on the wan side of pfsense?



  • Well thanks again, im quite new on it but this topology that i showed is the one i thought would work  :P

    What would u suggest for me? The main point is having my dhcp server working with pfsense server, cuz right now my network has this dhcp server working fine, i just want to insert pfsense server to control the internet access with captive portal.


  • Rebel Alliance Global Moderator

    well then your connection should be like this

    internet – pfsense -- switch -- all other devices including your dhcp server.



  • I see.. so the internet will be on wan side of pfsense? Ill do the tests and let u know the results.

    i was a bit confused about the topology cuz i have my dhcp server combined with dns.


  • Rebel Alliance Global Moderator

    Does your dhcp server also do NAT for your network, or route your other devices that are on public IPs?

    pfsense is designed to be your networks gateway/firewall to the internet.  It can be used as just an internal router/bridge/firewall - but by default its going to expect your internet to be on its WAN, and then NAT all your devices to your public IP behind it.

    I am guessing your dhcp and if it does dns that is maybe a AD DC?  If so it should be behind your gateway/firewall - and you can just have it forward its external dns to pfsense, or outside for public dns.  And all your internal clients would still use it for your internal AD dns, etc.


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