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    Tagged & Untagged traffic on a LAGG interface

    Scheduled Pinned Locked Moved General pfSense Questions
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    • JKnottJ Offline
      JKnott @alan.t
      last edited by

      @alan-t

      Why is there a problem? The only significant difference between tagged and untagged frames is the contents of the Ethertype/Length field.

      PfSense running on Qotom mini PC
      i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
      UniFi AC-Lite access point

      I haven't lost my mind. It's around here...somewhere...

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      • johnpozJ Offline
        johnpoz LAYER 8 Global Moderator
        last edited by johnpoz

        There is no such recommendation.. Now some people are of the mindset that hey if your going to do vlans on an interface, don't do native on it.

        But from a tech point of view there is nothing wrong with having "1" untagged vlan on an interface and any other vlans tagged.

        Whatever you feel most comfortable with.. I personally always run native on interface, and then if need to add vlans to that interface they are tagged. If I was only going to use 1 network on an interface - why would I bother tagging it?

        But then again if your then going to run vlans on an interface, sure if you want to tag them all - so you know hey this is a vlan interface.. That is fine too, and I can see sure why not. So whatever way you want to do it.. The nice thing about running a native vlan on an interface is hey you know you can always just plug anything into that interface and talk to that untagged IP.

        if the only networks on that port are tagged.. You can not ust plug a laptop into and say get a dhcp IP and talk to it. You have to know what tag to use.. So do whatever you want - just ya can't run more than 1 untagged network on an interface.. That not good! ;)

        An intelligent man is sometimes forced to be drunk to spend time with his fools
        If you get confused: Listen to the Music Play
        Please don't Chat/PM me for help, unless mod related
        SG-4860 24.11 | Lab VMs 2.8, 24.11

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        • A Offline
          alan.t
          last edited by

          Thanks for the input everyone.

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          • stephenw10S Offline
            stephenw10 Netgate Administrator
            last edited by stephenw10

            Yeah, there's certainly nothing that LAGG specific about that advice.

            It is generally said to be better to avoid tagged and untagged traffic on the same interface because it's much easier to end up with a bad config that sends traffic where it shouldn't go by doing that. Usually by untagging something in a switch that shouldn't be.
            If your switches are configured correctly (and don't have broken firmware ๐Ÿ˜‰ ) it's not a problem.

            https://docs.netgate.com/pfsense/en/latest/book/vlan/vlans-and-security.html

            Steve

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            • JKnottJ Offline
              JKnott @stephenw10
              last edited by

              @stephenw10 said in Tagged & Untagged traffic on a LAGG interface:

              It is generally said to be better to avoid tagged and untagged traffic on the same interface

              Actually, it's very common with VoIP phones sharing the same connection with a computer. Same with access points with multiple SSIDs.

              PfSense running on Qotom mini PC
              i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
              UniFi AC-Lite access point

              I haven't lost my mind. It's around here...somewhere...

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              • johnpozJ Offline
                johnpoz LAYER 8 Global Moderator
                last edited by johnpoz

                ^ agreed.. It all depends on the environment and what the admin likes to do, etc.. But agree with JKnott - its not uncommon to see lots of setups where native and tagged on the same interface.

                I sure wouldn't go out of my way to make sure there is only tagged on an interface, etc. Unless that is how you want to setup your network.. But from again from tech point of view its fine.

                The point of about easier to make mistakes - well that is admin problem, not a tech problem.. Just as easy to F up your config with vlans only or native and vlans on it if you ask me ;)

                An intelligent man is sometimes forced to be drunk to spend time with his fools
                If you get confused: Listen to the Music Play
                Please don't Chat/PM me for help, unless mod related
                SG-4860 24.11 | Lab VMs 2.8, 24.11

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                • stephenw10S Offline
                  stephenw10 Netgate Administrator
                  last edited by

                  Indeed, it's not uncommon. But if you can avoid it simply by using all tagged VLANs on a link it's better to do so IMO. It's usually trivial to configure and might save you a heap of time later.

                  Steve

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                  • JKnottJ Offline
                    JKnott @stephenw10
                    last edited by

                    @stephenw10 said in Tagged & Untagged traffic on a LAGG interface:

                    It's usually trivial to configure and might save you a heap of time later.

                    How? If you don't have native, you have to configure the interface for none and then create an additional VLAN to make up for it. In the case of VoIP phones or multiple SSIDs, you'd normally have the main LAN on the native connection and use a VLAN for the phone or 2nd SSID. Other than perhaps changing the MAC, is there any difference between configuring for native or VLAN?

                    PfSense running on Qotom mini PC
                    i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                    UniFi AC-Lite access point

                    I haven't lost my mind. It's around here...somewhere...

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                    • johnpozJ Offline
                      johnpoz LAYER 8 Global Moderator
                      last edited by

                      I can say for sure I have seen many a tech lock himself out trying to get rid of a native vlan ;)

                      And then have to go console in ;)

                      An intelligent man is sometimes forced to be drunk to spend time with his fools
                      If you get confused: Listen to the Music Play
                      Please don't Chat/PM me for help, unless mod related
                      SG-4860 24.11 | Lab VMs 2.8, 24.11

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                      • stephenw10S Offline
                        stephenw10 Netgate Administrator
                        last edited by

                        I hate the term 'native VLAN', it's used to mean at least two conflicting things. I assume here you mean untagged traffic.

                        In pfSense it's trivial to simply not assign the parent interface. You have to create an additional VLAN for that traffic sure.

                        The difference between using untagged traffic and and tagged VLAN is that it's far more likely traffic will leak from a VLAN to untagged then between tagged VLANs.
                        There is a while thread on here about a switch that does just that. I have one.

                        It's entirely up to the user. Just something to be aware of.

                        Steve

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                        • johnpozJ Offline
                          johnpoz LAYER 8 Global Moderator
                          last edited by

                          @stephenw10 said in Tagged & Untagged traffic on a LAGG interface:

                          leak from a VLAN to untagged

                          If you have such a switch.. replacement would be the correct solution to that problem ;)

                          An intelligent man is sometimes forced to be drunk to spend time with his fools
                          If you get confused: Listen to the Music Play
                          Please don't Chat/PM me for help, unless mod related
                          SG-4860 24.11 | Lab VMs 2.8, 24.11

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                          • stephenw10S Offline
                            stephenw10 Netgate Administrator
                            last edited by

                            Yup. Fortunately I paid almost nothing for it so relegating it to 'unmanaged' status is not really a problem for me. ๐Ÿ˜‰

                            Steve

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                            • JKnottJ Offline
                              JKnott @stephenw10
                              last edited by JKnott

                              @stephenw10 said in Tagged & Untagged traffic on a LAGG interface:

                              There is a while thread on here about a switch that does just that. I have one.

                              That is a well known defective switch. TP-Link had the same problem with an access point as well. I haven't heard of that happening with any other brand. Again though, if you're running VLANs on a LAN, you're still going to need untagged to talk to many devices that do not work with VLANs.

                              BTW, you can do what I did with my TP-Link switch. I configured it as a data tap, where that tagged VLAN problem is not an issue.

                              PfSense running on Qotom mini PC
                              i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                              UniFi AC-Lite access point

                              I haven't lost my mind. It's around here...somewhere...

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