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    WAN DHCP briefly assigns IP in the same subnet as LAN

    Scheduled Pinned Locked Moved DHCP and DNS
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    • J
      Jarhead @pfpv
      last edited by

      @pfpv It's not gonna cause any problems. It's not like you can connect to anything until the modem comes up anyway.

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      • R
        rcoleman-netgate Netgate @pfpv
        last edited by

        @pfpv said in WAN DHCP briefly assigns IP in the same subnet as LAN:

        I am pretty sure it's my cable modem. I explained the possible reason. It goes into routed mode first while booting, then it goes into bridge mode.

        This is normal, though.

        Ryan
        Repeat, after me: MESH IS THE DEVIL! MESH IS THE DEVIL!
        Requesting firmware for your Netgate device? https://go.netgate.com
        Switching: Mikrotik, Netgear, Extreme
        Wireless: Aruba, Ubiquiti

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        • P
          pfpv @Jarhead
          last edited by

          @jarhead said in WAN DHCP briefly assigns IP in the same subnet as LAN:

          @pfpv It's not gonna cause any problems. It's not like you can connect to anything until the modem comes up anyway.

          Why did it cause the LAN DHCP server crash and DynDNS update? Keep in mind I am on dual-WAN with failover and at that time the primary WAN was on DSL. I think pfSense was confused.

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          • J
            Jarhead @pfpv
            last edited by

            @pfpv In that case change your LAN address.
            I always use the 10/8 addresses based on the owners birthday.
            So if your birthday was today, I would make your LAN address 10.7.24.0/2x.
            Been doing this for years and have never overlapped or reused an address yet! I still expect it to come someday though.

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            • S
              serbus
              last edited by

              Hello!

              Check the DHCP Client Configuration in the Interface...Maybe...

              Firefox_Screenshot_2022-07-24T22-52-00.604Z.png

              John

              Lex parsimoniae

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              • J
                Jarhead @serbus
                last edited by

                @serbus Excellent point! Forgot that was there. Would save from having to change the subnet.

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                • P
                  pfpv @Jarhead
                  last edited by

                  @jarhead
                  Thanks for the tip about 10/8 addresses! Quite useful.

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                  • P
                    pfpv @serbus
                    last edited by

                    @serbus said in WAN DHCP briefly assigns IP in the same subnet as LAN:

                    Hello!

                    Check the DHCP Client Configuration in the Interface...Maybe...

                    Firefox_Screenshot_2022-07-24T22-52-00.604Z.png

                    John

                    Thank you! This solves it. I should browse settings that are set and forgotten more often. It could have saved me from another earlier issue.

                    Would you happen to know the details about the "Alias IPv4 address" setting in the same tab? The Netgate docs say

                    This value used as a fixed IPv4 alias address by the DHCP client since a typical IP Alias VIP cannot be used with DHCP. This can be useful for accessing a piece of gear on a separate, statically numbered network outside of the DHCP scope. One example would be for reaching a cable modem management IP address.

                    I set to 192.168.100.1 which is the modem management interface when in bridge mode but going there brought me to pfSense login page. I am confused.

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                    • R
                      rcoleman-netgate Netgate @pfpv
                      last edited by

                      @pfpv Try setting it to 100.2

                      Ryan
                      Repeat, after me: MESH IS THE DEVIL! MESH IS THE DEVIL!
                      Requesting firmware for your Netgate device? https://go.netgate.com
                      Switching: Mikrotik, Netgear, Extreme
                      Wireless: Aruba, Ubiquiti

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                      • P
                        pfpv @rcoleman-netgate
                        last edited by pfpv

                        @rcoleman-netgate said in WAN DHCP briefly assigns IP in the same subnet as LAN:

                        @pfpv Try setting it to 100.2

                        Yes, thank you. Once you wrote it, it suddenly became very logical. It works now.

                        I have always had a virtual IP on WAN 192.168.100.5/24 and it seemed to let me access 192.168.100.1. Only now I read in the instructions that "a typical IP Alias VIP cannot be used with DHCP".

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