PFSense DHCP Server is Dysfunctional - Ignoring Range

Discussion in 'Networking & Security' started by Sauntache, Aug 22, 2013.

  1. Sauntache

    Sauntache n00b

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    May 3, 2013
    I buggered some things up, and ended up doing a factory reset in PFSense. Now there's something wrong with the DHCP server: I have the range set to X.X.X.50 - X.X.X.100, but it's not handing out IPs to computers in that range. In fact it's not handing them out at all. They're still getting IP addresses from somewhere (X.X.X.30, 31 etc.), but there is a huge delay, and they don't show up in PFSense's list of active DHCP leases. PFSense has only distributed one IP, and that was to my printer.

    Why is it not providing DHCP leases to my PCs now?

    Where are the PCs getting their IPs from if not from PFSense? From Windows?
     
  2. Sauntache

    Sauntache n00b

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    May 3, 2013
    OK, suddenly one PC has changed from the phantom .31 lease to a proper lease from PFSense. I had already restarted the PC and the router, and it had stayed on .31, so why does it choose to change it right now in mid use?

    EDIT: Had windows generated it's own lease PC-side (from before the router was configured) which I had to wait for to expire?
     
  3. TCM

    TCM Gawd

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    Nov 10, 2011
    Normally a DHCP server "denies" requests for specific addresses if it has no range for it. Of course it can't deny a client just picking any address, but it sends a DHCPNAK which the client is supposed to honor if it follows protocol.

    Could it be that you have another DHCP server running somewhere? A proper DHCP server is sending a server ID with each reply so you could sniff the traffic and look for pfsense's ID.

    DHCP really is just a first wins protocol. If you have multiple servers and they all think they're authoritative, the first request that makes it to the client is it.
     
  4. Sauntache

    Sauntache n00b

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    None, except for any DHCP serving windows itself might have been doing (I don't fully understand how it operates).

    Anyway, the remaining machines that had non-PFSense leases have all come over to PFSense now.