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

    Source IP 0.0.0.0.0 OR 127.0.0.1 AND ports 137, 138, 3128 dropped packets

    Scheduled Pinned Locked Moved General pfSense Questions
    7 Posts 4 Posters 7.7k Views
    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.
    • X
      XabiX
      last edited by

      Hello Team,

      I have a few lines in the fw logs that I don't understand. There should be a way to either stop these or allow them if they are normal. Using Pfsense 2.4.2-RELEASE-p1 on Proxmox.

      1/ Pfsense is the source? What can I do to understand where this traffic is coming from?

      Feb 5 10:22:27	LAN	USER_RULE (1513358118)	  0.0.0.0:138	  0.255.255.255:138	UDP
      Feb 5 10:22:27	LAN	USER_RULE (1513358118)	  0.0.0.0:137	  0.255.255.255:137	UDP
      Feb 5 10:22:27	LAN	USER_RULE (1513358118)	  0.0.0.0:137	  0.255.255.255:137	UDP
      Feb 5 10:22:27	LAN	USER_RULE (1513358118)	  0.0.0.0:137	  0.255.255.255:137	UDP
      Feb 5 10:22:27	LAN	USER_RULE (1513358118)	  0.0.0.0:137	  0.255.255.255:137	UDP
      Feb 5 10:22:27	LAN	USER_RULE (1513358118)	  0.0.0.0:137	  0.255.255.255:137	UDP
      

      Not sure why Pfsense is sending some Netbios traffic. How can I stop of being sent if it's not legitimate/necessary traffic?

      2/ I have many lines from Pfsense again to my Wifi laptops. Out of connection traffic which seems coming from Squid. Should I increase a timer or whitelist my internal networks in Squid to avoid such messages between internal interfaces?

      	Feb 5 09:38:48	► WIFI	Default deny rule IPv4 (1000000104)	  127.0.0.1:3128	  10.20.30.2:54788	TCP:RA
      	Feb 5 09:09:17	► WIFI	Default deny rule IPv4 (1000000104)	  127.0.0.1:3128	  10.20.30.2:41544	TCP:FA
      

      Thank you in advance for your help

      XabiX
      logs.jpg
      logs.jpg_thumb

      Pfsense (latest 2.4) running on Proxmox 5.2 with Intel I350 quad ports
      Click on the Website (small planet) to see my network diagram

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

        Those packets from 127.0.0.1 3128 look to be out of state from the proxy?  3128 is proxy..

        But from 0.0.0.0 to a broadcast address.. Pfsense out of the box has nothing that would talk or listen on 137 or 138 that most likely something on your lan sending to broadcast - which yes pfsense would see that traffic.

        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
        • K
          kpa
          last edited by

          The 0.0.0.0 source address is also used by a DHCP client when the client has no lease at all. It will broadcast UDP discovery messages on the connected network to discover DHCP servers in that network and the source address in those messages is set to 0.0.0.0 because it has no other source address to use. Something on your network is doing the same but with NetBIOS/MS filesharing ports.

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

            The 0.0.0.0 address is used when a device does not yet know it's IP address.  It's used, for example, with DHCP, until an address has been received.  However, the destination would be  the broadcast address 255.255.255.255.  I have no idea why 0.255.255.255 is used.  The loop back address, 127.0.0.1 or any address in 127.0.0.0 /8 for that matter, is used within the device for various things.

            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...

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

              Good catch on the 0.255.255.255

              Why don't you sniff that traffic and find out what mac its coming from so you can see what is sending it.

              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
              • JKnottJ
                JKnott
                last edited by

                0.255.255.255 is a type of broadcast address.  It wouldn't have a hardware MAC address.  I believe this may go back to the very early days, when 0.0.0.0 was a broadcast address.

                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...

                1 Reply Last reply Reply Quote 0
                • X
                  XabiX
                  last edited by

                  For point 1, then the question would be: Is 0.255.255.255 legitimate traffic that I should allow so they will disappear from those logs and potentially fix a traffic currently being blocked?
                  If not I agree I should look to understand who is sending those. (so far my captures where empty with filter "0.255.255.255 | 127.0.0.1 | 0.0.0.0" so I need to let him run longer)

                  FYI I have noted this on my Pfsense:

                  netstat -n | grep 137
                  tcp4       0      0 192.168.1.10.39316     137.254.104.115.80     TIME_WAIT
                  tcp4       0      0 192.168.1.10.17033     45.79.137.197.443      ESTABLISHED
                  
                  netstat -n | grep 138
                  tcp4       0      0 127.0.0.1.3129         10.0.0.2.61383         FIN_WAIT_2
                  

                  1/ Maybe is then normal to have 127.0.0.1:3129 or 3128 ? Do you also have this on your Pfsense box? (FYI 192.168.1.10 is my WAN IP behind the DSL box)

                  For point 2, do you think it worth trying these Squid options by adding my private IP ranges (as 10.20.30/24)?

                  • Bypass Proxy for Private Address Destination

                  • Bypass Proxy for These Source IPs

                  It's interesting not critical issue but I like to understand what is happening and have clean logs too :)

                  PS (EDIT): Attached the NAT rules created for Ipsec. I am wondering if this 127/8 couldn't be the reason. I will remove the 1st line as I am using OpenVPN and not IPsec tunnel

                  nat.jpg
                  nat.jpg_thumb
                  sockets.jpg
                  sockets.jpg_thumb

                  Pfsense (latest 2.4) running on Proxmox 5.2 with Intel I350 quad ports
                  Click on the Website (small planet) to see my network diagram

                  1 Reply Last reply Reply Quote 0
                  • First post
                    Last post
                  Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.