IP conflict error on clients

  • Hi, first of all I didn't know where should I open this topic so I put it here, Sorry about that =/

    I have a problem and couldn't find or wasn't be able to find the answer of my questions on this forum. The problem is that I can't connect to wan after installing pfSense, and the clients get "ip conflict" error, and than I can't connect to pfSense since I reset it to factory defaults… Btw there is two ethernet cards on my server computer 1 of them internal onboard the other is external PCI Card. I wonder on board ethernet cards don't work properly on pfSense.

    Also there is second problem, I can't set onboard ethernet card as wan, if I do that I can't connect it to set it on webui. So I dunno what should I do.

  • LAYER 8 Global Moderator

    What cards don't work with pfsense?

    Are you talking about a box your running pfsense on, or some client machine on your network?

    As to IP conflict that has nothing to do with card working with pfsense or not..  Means you have a conflict (2 machines with same IP)

    You need to be clear which nic your setting as wan and which is lan when you setup pfsense.

    The wan one should be connected to your internet connection, and your lan is your network - pfsense defaults to - do you have something else on your network with that IP?

    What are you plugging the pfsense wan nic into?  A modem, a router?  Is your modem/router already doing nat or will pfsense get a public IP.  Common setup is wan would be dhcp on pfsense.

    Some details of your networking devices and address space already in use would be helpful.  What is the make and model number of the device your wanting to be pfsense wan?  And assume your plugging its lan into a switch?

  • -The network wan card connecting the network plugging into freezes the network and the machines cannot get adressed by modem, and the computers on the network plugging into pfSense get the message "ip conflict".
    -No, not the box, the clients connect to pfSense, also the other network that pfSense plugged into modem.
    -yea, with the same ip, when the machines connect to the pfSense one by one, the past connected machine errors "ip conflict" detected when the new one connects.
    -I set them correctly, by watching "http://www.youtube.com/watch?v=BBE-Fr7P_8I" this video, also I tested it, it works but after a little while it block every connections both networks, and it keeps blocking the network if I don't disconnect the pfSense.
    -I have changed default ip to and set everything on pfSense web ui.
    -I plug wan nic into the network that connected to modem

    I have installed pfSense a new brand computer and used one onboard nic card and an external tp-link 3200 nic card. I didn't have the problem that I'm mentioning here. I start to think that the problem occurs because of old machines, or old brand models. And today I have seen some problems, so I'll try to fix it after I have fixed the problems.

    Also one thing happend today, I was setting the computers in my networ in whitelist, and I shut the computer after I have done setting it. I got ip conflict message when I'm setting the next computer and it got the past ip, was on the computer I set before. But it fixed it by itself when I clicked it "ok", also didn't be need to clicked on it. it fixed itself.

    I use dhpc, do you think that ipconflict occurs because of that?

  • Banned


    -I have changed default ip to and set everything on pfSense web ui. is completely invalid IP for LAN. You just don't invent things, there's RFC1918 for non-routable IPs for local networks (ab)use.

    NetRange: -
    NetName:        DNIC-RNET-192-100-100
    NetHandle:      NET-192-100-100-0-1
    Parent:         NET-192-0-0-0-0
    NetType:        Direct Assignment
    RegDate:        1991-04-12
    Updated:        2009-04-02
    Ref:            http://whois.arin.net/rest/net/NET-192-100-100-0-1
    OrgName:        DoD Network Information Center
    OrgId:          DNIC
    Address:        3990 E. Broad Street
    City:           Columbus
    StateProv:      OH
    PostalCode:     43218
    Country:        US
    Updated:        2011-08-17
    Ref:            http://whois.arin.net/rest/org/DNIC

    :o ::)

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