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    Any reason to allow multicast on WAN?

    Scheduled Pinned Locked Moved Firewalling
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    • K
      kingrazor
      last edited by

      I see traffic from the WAN address to the multicast address (224.0.0.1) for both ICMP and IGMP traffic. Is there any circumstance where I would want to allow this?

      While on the subject of stuff that is blocked by default, is there any reason to allow DHCP traffic from 0.0.0.0 over port 68 to 255.255.255.255 port 67 on a LAN interface? In this case I'm using a DHCP server within the LAN interface and have DHCP disabled on pfsense.

      I assume the default rules are fine and I'm not seeing any problems. Just asking for my own education.

      johnpozJ 1 Reply Last reply Reply Quote 0
      • johnpozJ
        johnpoz LAYER 8 Global Moderator @kingrazor
        last edited by johnpoz

        There are hidden rules that allow dhcp when you enable dhcp server, and on wan for dhcp client, etc.

        No there would be no reason to allow for multicast on wan.. It sure not going to go anywhere - and pfsense. If the noise is bothering you in the log, you can just create a rule to block it and not log.

        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

        K JKnottJ 2 Replies Last reply Reply Quote 1
        • K
          kingrazor @johnpoz
          last edited by

          @johnpoz said in Any reason to allow multicast on WAN?:

          There are hidden rules that allow dhcp when you enable dhcp server, and on wan for dhcp client, etc.

          No there would be no reason to allow for multicast on wan.. It sure not going to go anywhere - and pfsense. If the noise is bothering you in the log, you can just create a rule to block it and not log.

          Kinda figured, but good to know anyway. Thanks!

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          • johnpozJ
            johnpoz LAYER 8 Global Moderator @kingrazor
            last edited by

            I personally don't like seeing all the noise that default logging produces, so I turn off default logging and just put in my own rule that logs what I want to see which is common udp ports, and tcp traffic with syn set.

            blocks.jpg

            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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            • JKnottJ
              JKnott @johnpoz
              last edited by

              @johnpoz said in Any reason to allow multicast on WAN?:

              No there would be no reason to allow for multicast on wan..

              On IPv6, allowing multicast is essential. It won't work without the various multicasts.

              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...

              johnpozJ 1 Reply Last reply Reply Quote 0
              • johnpozJ
                johnpoz LAYER 8 Global Moderator @JKnott
                last edited by johnpoz

                And what does that have to do with anything?

                He is clearly blocking it now anyway.. Pfsense would enable by hidden rule the requirements for IPv6 to function. If it was actually enabled on pfsense.

                (224.0.0.1) for both ICMP and IGMP traffic

                Is not IPv6, and in what sense is multicast required for IPv6? Where in the rfc does it say that? ICMPv6 yes - multicast where?

                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

                JKnottJ 1 Reply Last reply Reply Quote 0
                • JKnottJ
                  JKnott @johnpoz
                  last edited by

                  @johnpoz said in Any reason to allow multicast on WAN?:

                  multicast where?

                  Things like router and neighbour solicitation. For example, the all routers multicast, all hosts multicast, etc.. Then there's solicited node multicast, to see if an address is in use. That's just off the top of my head. One other thing to bear in mind is there are no broadcasts with IPv6, with that function provided by all hosts multicast.

                  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...

                  johnpozJ 1 Reply Last reply Reply Quote 0
                  • johnpozJ
                    johnpoz LAYER 8 Global Moderator @JKnott
                    last edited by johnpoz

                    ICMPv6 to a multicast address.. Say

                    # IPv6 ICMP is not auxiliary, it is required for operation
                    # See man icmp6(4)
                    # 1    unreach         Destination unreachable
                    # 2    toobig          Packet too big
                    # 128  echoreq         Echo service request
                    # 129  echorep         Echo service reply
                    # 133  routersol       Router solicitation
                    # 134  routeradv       Router advertisement
                    # 135  neighbrsol      Neighbor solicitation
                    # 136  neighbradv      Neighbor advertisement
                    pass  quick inet6 proto ipv6-icmp from any to any icmp6-type {1,2,135,136} tracker 1000000107 keep state
                    
                    # Allow only bare essential icmpv6 packets (NS, NA, and RA, echoreq, echorep)
                    pass out  quick inet6 proto ipv6-icmp from fe80::/10 to fe80::/10 icmp6-type {129,133,134,135,136} tracker 1000000108 keep state
                    pass out  quick inet6 proto ipv6-icmp from fe80::/10 to ff02::/16 icmp6-type {129,133,134,135,136} tracker 1000000109 keep state
                    pass in  quick inet6 proto ipv6-icmp from fe80::/10 to fe80::/10 icmp6-type {128,133,134,135,136} tracker 1000000110 keep state
                    pass in  quick inet6 proto ipv6-icmp from ff02::/16 to fe80::/10 icmp6-type {128,133,134,135,136} tracker 1000000111 keep state
                    pass in  quick inet6 proto ipv6-icmp from fe80::/10 to ff02::/16 icmp6-type {128,133,134,135,136} tracker 1000000112 keep state
                    pass in  quick inet6 proto ipv6-icmp from :: to ff02::/16 icmp6-type {128,133,134,135,136} tracker 1000000113 keep state
                    

                    Is not all Multicast - and sure isn't to 224.0.0.1

                    As I stated if it was required for IPv6 to work, the rules would already be there - hidden.

                    His blocking of IPv4 multicast noise is not going to break anything..

                    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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