WAN Failed to Get DHCP IP Address (Solved)



  • So, yesterday I turned on my new ISP cable service and I could not get WAN to obtain DHCP IP address...could not figured that out (posting this from a friend's home)...I am baffled by this...what could it be? I keep getting 0.0.0.0! I am on pfSense 2.4, and my machine had been not used since last update in December!



  • Check the Ethernet cable if all's good, Disable wan and re-able it in the Interfaces settings.

    (does he get a valid IP if he plugs it directly into a computer/Laptop etc. ?)



  • @Polarmike said in WAN Failed to DHCP IP Address:

    Check the Ethernet cable if all's good, Disable wan and re-able it in the Interfaces settings.

    (does he get a valid IP if he plugs it directly into a computer/Laptop etc. ?)

    Yes, cable is good and yes; I get valid IP when plugged directly with a computer or my Mikrotik.


  • LAYER 8 Global Moderator

    Did you power cycle the cable modem between changing devices too it?

    If you connect say pc to cable modem and get public IP, between you can connect pfsense you will almost for sure have to power cycle the cable modem... They almost always pair up with the device connected to them, when you want to change that device you need to power cycle them because the mac of the device is going to be different.



  • @johnpoz said in WAN Failed to DHCP IP Address:

    Did you power cycle the cable modem between changing devices too it?

    If you connect say pc to cable modem and get public IP, between you can connect pfsense you will almost for sure have to power cycle the cable modem... They almost always pair up with the device connected to them, when you want to change that device you need to power cycle them because the mac of the device is going to be different.

    Yes, I did power cycled the cable modem...in fact, I was on the phone with the ISP as I was baffled...they saw the pfSense requests an IP, then it went to 0.0.0.0. So, I had wondered whether the IP address issued was in my block list...why the 0.0.0.0!



  • If you're dealing with a smaller home network, and right now you just need to get it working, you can get around this for now by assigning a Static IP (until you get it figured out)



  • @NollipfSense said in WAN Failed to Get DHCP IP Address:

    why the 0.0.0.0

    That's what address devices use, until they're assigned an address. Entirely normal, though it should get an assigned address.

    What do you mean by "then it went to 0.0.0.0"? Did that come back from the ISP? Did pfSense just use it, without accepting an offered address? This is where packet captures really come in handy, to see what's actually on the wire.


  • LAYER 8 Global Moderator

    @JKnott said in WAN Failed to Get DHCP IP Address:

    This is where packet captures really come in handy, to see what's actually on the wire.

    Exactly!!! you see pfsense send the discover - so what did they offer??



  • Well, it turned out to be patience that was needed...had I wait, I would see on the dashboard that the negotiations between the cable modem and the pfSense were going on, changing WAN IP from n/a to 0.0.0.0, then, 192.168.100.10...doing that rotation a couple of times, then finally getting the proper IP address...all is good.


  • LAYER 8 Global Moderator

    So you cable modem wasnt actually connected to the internet yet.. ;)

    Yeah you have to wait til its actually on the internet before it can give something behind an IP... 192.168.100.x is what it gives clients when its booted but not connected to internet.


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