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    Multiple WAN DNS issue when primary fails

    Scheduled Pinned Locked Moved Routing and Multi WAN
    24 Posts 9 Posters 18.5k Views
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    • S
      Supermule Banned
      last edited by

      redmine.pfsense.org and report it there….

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      • pttP
        ptt Rebel Alliance
        last edited by

        I don't know if this can help to "KyferEz" with his problem, but i have configured my pfSense this way, and don't have noticed DNS issues

        pfS_DNS.PNG
        pfS_DNS.PNG_thumb

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        • J
          jfine
          last edited by

          @ptt Would you mind taking a screen shot of two additional pages to help confirm what I'm seeing? Diagnostics -> Routes (IPv4 table) and Status -> Interfaces. I'm curious how your four DNS servers get assigned.

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          • pttP
            ptt Rebel Alliance
            last edited by

            Here the Routes SS ( DNS marked in red )

            In Status -> Interfaces, all DNS servers are listed in WAN1,  WAN2 doesn't show any DNS ( the "ISP DNS servers" dont even appear in WAN2 )

            pfS_Routes.PNG
            pfS_Routes.PNG_thumb

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            • L
              lolek
              last edited by

              Hello,
              I see the @ptt routing table, I think the dns are correct, just in my routing table.
              I noticed in my pfsense machine, that the default route in Diagnostics -> Routes (IPv4 table) remains the same whatever WAN is online(I unplugged every WAN to test), maybe a problem in Gateway Groups, look in my gateway groups, I think is correct.
              Also for my 2 gateways I don't check "default route" for these.
              Regards

              gw.jpg
              gw.jpg_thumb
              gw1.jpg
              gw1.jpg_thumb

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              • luckman212L
                luckman212 LAYER 8
                last edited by

                I didn't read this entire thread word for word but, I have seen similar issues.  It seems (am I correct??)  that pfSense assigns static routes to specific DNS servers if a specific gateway is selected on the General setup page.  I assume this is so 'apinger' can detect if a GW is really down when pings to that monitor IP start failing instead of sending them over the other connection??  not sure.  but add me to the "me too" list of people who would like to know the "correct" way to assign these values.

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                • C
                  cmb
                  last edited by

                  @luckman212:

                  I didn't read this entire thread word for word but, I have seen similar issues.  It seems (am I correct??)  that pfSense assigns static routes to specific DNS servers if a specific gateway is selected on the General setup page.  I assume this is so 'apinger' can detect if a GW is really down when pings to that monitor IP start failing instead of sending them over the other connection??  not sure.  but add me to the "me too" list of people who would like to know the "correct" way to assign these values.

                  You must have at least one DNS server pointing to each WAN if you're using the DNS forwarder as your clients' DNS server. The WAN you pick sets a static route so the firewall goes out that WAN to reach that DNS server. You cannot use a single DNS server IP on more than one WAN (though I'm not sure offhand if there's input validation to prevent that, it won't work). There are exceptions to that if you get into policy routing traffic initiated by the firewall but that's more complex than what most people will get into.

                  If you're not using the DNS forwarder, your internal DNS servers must be going out of a failover or load balancing gateway group so you still have DNS when one fails.

                  @jfine:

                  Also like @KyferEz noted, although the routing shows each DNS IP associated with the appropriate gateway (Diag->Routes), the interface status (Status->Interfaces) shows all DNS IPs with the first WAN connection, which I believe might be a bug.

                  That's just how it's displayed, all the system's DNS servers show there.

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                  • J
                    jfine
                    last edited by

                    @cmb
                    Thanks so much for that clarification. It makes sense now.

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                    • K
                      KyferEz
                      last edited by

                      FINALLY FOUND THE SOLUTION TO MY PROBLEM TODAY!!!

                      In every guide and instruction sheet I have read for configuring multiwan, not once was there instructions that included this necessary and very important step in a way that a beginner could easily understand: Edit the default LAN rule in Firewall->Rules by clicking edit on the rule that has a row that contains "LAN net". Then change Gateway setting drop-down to whatever you named the gateway you created with the Wan1 fallover to Wan2.

                      Here is a link to a simple and basic working guide for multiwan setup on pfSense 2.0. The top of the guide is for 1.2, but scroll about half-way down to see the 2.0 guide: http://skear.hubpages.com/hub/Dual-Wan-Router-How-To-Build-One-On-a-Budget. Combine that info with the other guides out there for setting up traffic shaping and it works great!

                      Thanks!

                      Home Lab:
                      Dell r310 Quad core 32GB RAM & 4 3TB SAS
                      Intel Server 2 Quad core 24GB RAM & 6 2TB SAS
                      Dell r410 Dual Hex core 24GB RAM & 4 1TB SAS
                      HP Proliant DL380 Gen7 2 Quad core 24GB RAM & 6 1TB SAS
                      28port POE Gb Cisco SG300-28P
                      24port POE Gb Managed Netgear
                      24port Catalyst Switch
                      Cicso 1900 router
                      OPNsense
                      Sophos UTM
                      6 NetScaler VPX3000
                      2 VOIP phones Cisco SPA500
                      Cisco Air SAP1602 AP

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                      • jimpJ
                        jimp Rebel Alliance Developer Netgate
                        last edited by

                        The instructions for 2.0 here:
                        http://doc.pfsense.org/index.php/Multi-WAN_2.0

                        Mention using the rules twice – once in the summary of required steps, and again later under "Firewall Rules"

                        It even mentions editing your existing rule and changing the gateway.

                        Not sure what doc you were reading that skipped it.

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                        • K
                          KyferEz
                          last edited by

                          You misread my statement. I said it's not there in a way a beginner with pfSense can understand what to do. I did not understand what exactly was meant by those instructions (and had thus gotten it wrong) until I read the guide I linked to where the writer detailed Exactly How to create the Firewall Rules…

                          That step is just confusing in the 2.0 docs. (edit: likely because I'm not engrossed in large corporate network configuration daily ;) I tend to work with smaller companies with 3-10 employees, but this one had outgrown a single dsl line)

                          Home Lab:
                          Dell r310 Quad core 32GB RAM & 4 3TB SAS
                          Intel Server 2 Quad core 24GB RAM & 6 2TB SAS
                          Dell r410 Dual Hex core 24GB RAM & 4 1TB SAS
                          HP Proliant DL380 Gen7 2 Quad core 24GB RAM & 6 1TB SAS
                          28port POE Gb Cisco SG300-28P
                          24port POE Gb Managed Netgear
                          24port Catalyst Switch
                          Cicso 1900 router
                          OPNsense
                          Sophos UTM
                          6 NetScaler VPX3000
                          2 VOIP phones Cisco SPA500
                          Cisco Air SAP1602 AP

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