Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    PfSense not replying to UDP traceroute on WAN

    Scheduled Pinned Locked Moved General pfSense Questions
    17 Posts 5 Posters 6.2k Views 2 Watching
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • T Offline
      travisbrackett
      last edited by

      In my traceroute, I'm using the WAN IP address, and the packet capture confirms that the destination IP is the same one assigned to my WAN interface.

      1 Reply Last reply Reply Quote 0
      • DerelictD Offline
        Derelict LAYER 8 Netgate
        last edited by

        Try rejecting, not passing. This works for me:

        ![Screen Shot 2018-03-02 at 4.20.26 PM.png](/public/imported_attachments/1/Screen Shot 2018-03-02 at 4.20.26 PM.png)
        ![Screen Shot 2018-03-02 at 4.20.26 PM.png_thumb](/public/imported_attachments/1/Screen Shot 2018-03-02 at 4.20.26 PM.png_thumb)

        Chattanooga, Tennessee, USA
        A comprehensive network diagram is worth 10,000 words and 15 conference calls.
        DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
        Do Not Chat For Help! NO_WAN_EGRESS(TM)

        1 Reply Last reply Reply Quote 1
        • johnpozJ Offline
          johnpoz LAYER 8 Global Moderator
          last edited by

          Yup same rule here..

          wantraceroute.png
          wantraceroute.png_thumb

          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

          1 Reply Last reply Reply Quote 0
          • DerelictD Offline
            Derelict LAYER 8 Netgate
            last edited by

            that's a lot of NTP traffic…. :)

            Chattanooga, Tennessee, USA
            A comprehensive network diagram is worth 10,000 words and 15 conference calls.
            DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
            Do Not Chat For Help! NO_WAN_EGRESS(TM)

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

              Yeah have a stratum 1 in the pool..

              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

              1 Reply Last reply Reply Quote 0
              • T Offline
                travisbrackett
                last edited by

                That did the trick! Thanks!

                1 Reply Last reply Reply Quote 0
                • T Offline
                  travisbrackett
                  last edited by

                  One weird thing I'm seeing is with Windows tracert which uses ICMP, pfSense sends a TTL expired reply when the request TTL is < 6, so I get a weird result where my pfSense firewall shows up 5 times. I don't want to reject ICMP packets, and I don't see a way to configure the TTL threshold. Anyone know of a remedy?

                  1 Reply Last reply Reply Quote 0
                  • DerelictD Offline
                    Derelict LAYER 8 Netgate
                    last edited by

                    I would need to see a packet capture of that.

                    Chattanooga, Tennessee, USA
                    A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                    DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                    Do Not Chat For Help! NO_WAN_EGRESS(TM)

                    1 Reply Last reply Reply Quote 0
                    • T Offline
                      travisbrackett
                      last edited by

                      Here you go. I've anonymized the pcap so 1.1.1.1 is the host running the traceroute, and 2.2.2.2 is my pfSense firewall. Looks like I was wrong and it stops sending a TTL expired, and starts replying, when the TTL is greater than 4.

                      Edit: Oops, there's a 1:1 NAT and the replies are probably the routers in between and the host the packets are being NATted to.

                      Edit: Packet capture on the LAN interface confirms this theory.

                      icmptraceroute_anonymized.pcap

                      1 Reply Last reply Reply Quote 0
                      • DerelictD Offline
                        Derelict LAYER 8 Netgate
                        last edited by

                        OK you're kind of all over the place. You state that pfSense responds in the negative with a TTL > 4. What, exactly am I looking for?

                        What interface was that pcap taken on?

                        Anonymizing MAC addresses? Really? I can't help you.

                        Chattanooga, Tennessee, USA
                        A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                        DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                        Do Not Chat For Help! NO_WAN_EGRESS(TM)

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

                          "One weird thing I'm seeing is with Windows tracert which uses ICMP, pfSense sends a TTL expired reply when the request TTL is < 6"

                          From where to where?

                          I trace through pfsense to internet all the time, never seen such a thing..

                          singlepfsenseintrace.png
                          singlepfsenseintrace.png_thumb

                          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

                          1 Reply Last reply Reply Quote 0
                          • A Offline
                            axsense2
                            last edited by

                            What was the resolution? I am having the same problem as in topic. Tracing PFSense from outside PFSense seems that it is not recognizing traces at all. Ping works fine. It can't be true that PFSense does not work with Traceroute in UDP mode... can it?

                            Ax.

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

                              Ah screenshot is missing - prob got lost when they updated the forum... You juts need to set a reject rule on your wan for the udp ports. When get back from lunch can post up a screenshot.

                              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

                              1 Reply Last reply Reply Quote 0
                              • A Offline
                                axsense2
                                last edited by

                                Got it... I think. I created Rejected rule for UDP between ports 33434 and 33634. It actually resolves the issue.

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

                                  yup... that is all you need to do.

                                  edit: for the next guy that finds this thread... I will post up screenshot of the rule
                                  tracerouterule.png

                                  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

                                  1 Reply Last reply Reply Quote 3
                                  • First post
                                    Last post
                                  Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.