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

    Outbound and inbound FTP stopped working

    Scheduled Pinned Locked Moved NAT
    45 Posts 3 Posters 11.7k 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.
    • johnpozJ
      johnpoz LAYER 8 Global Moderator
      last edited by

      Well validate that it still is - simple enough to do a sniff on wan, connect to ftp server and validate that it changes your IP to your public so it can connect with active

      So you can see in the active connection, sniffing on the wan, my public IP is sent in the port command..  Even though client sends private.

      Then in the passive connection I get told what IP to connect to, and the syn is sent from my side - helper has nothing to do with this sort of connection.  When your the client behind pfsense, only if the server was behind pfsense and it sent private would helper have to change the port and open it for the syn.

      If you are so clear on the active/passive ftp connectivity I would assume you would of already looked at simple sniff to see what is not working, what info is being sent or not sent, etc.

      I can tell you I have 2.1.5 running - and don't have any problem connecting to public ftp servers from behind pfsense.  And if I turn on a ftp server behind pfsense.. outside can connect to my ftp server active or passive.  All that is needed is simple forward to 21 of the server private ip.

      You can see in bottom 3 attachments, on the wan of pfsense passive is given as public IP, but server clearly sent its private..  So that is the helper at work changing that.  And the first attachments are client connecting to public IP outside pfsense where the helper changes port command for the active connection.

      active.png
      active.png_thumb
      clientactive.png
      clientactive.png_thumb
      passive.png
      passive.png_thumb
      outsideclient.png
      outsideclient.png_thumb
      outsidelisting.png
      outsidelisting.png_thumb
      serverpassivelanside.png
      serverpassivelanside.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
      • K
        kcpoole
        last edited by

        @johnpoz:

        Well validate that it still is - simple enough to do a sniff on wan, connect to ftp server and validate that it changes your IP to your public so it can connect with active

        So you can see in the active connection, sniffing on the wan, my public IP is sent in the port command..  Even though client sends private.

        Then in the passive connection I get told what IP to connect to, and the syn is sent from my side - helper has nothing to do with this sort of connection.  When your the client behind pfsense, only if the server was behind pfsense and it sent private would helper have to change the port and open it for the syn.

        If you are so clear on the active/passive ftp connectivity I would assume you would of already looked at simple sniff to see what is not working, what info is being sent or not sent, etc.

        I can tell you I have 2.1.5 running - and don't have any problem connecting to public ftp servers from behind pfsense.  And if I turn on a ftp server behind pfsense.. outside can connect to my ftp server active or passive.  All that is needed is simple forward to 21 of the server private ip.

        You can see in bottom 3 attachments, on the wan of pfsense passive is given as public IP, but server clearly sent its private..  So that is the helper at work changing that.  And the first attachments are client connecting to public IP outside pfsense where the helper changes port command for the active connection.

        Ok thanks. will try that and see what i can see. I do not have another host on the wan side of the firewall, (It is in a remote data centre),  so will have to set one up and sniff.
        That will also give me host outside the firewall to confirm that it is actually Pfsense causing the issue.

        Ken

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

          pfsense under diag, packet capture can do all the packet capture you need to do..

          If you need a host outside to confirm – just PM the info, happy to to do a test connection to it and tell you what I see active and passive what is being sent to the client, etc.

          packetcapture.png
          packetcapture.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
          • K
            kcpoole
            last edited by

            @johnpoz:

            pfsense under diag, packet capture can do all the packet capture you need to do..

            If you need a host outside to confirm – just PM the info, happy to to do a test connection to it and tell you what I see active and passive what is being sent to the client, etc.

            Ok thanks
            Will let you know

            Ken

            1 Reply Last reply Reply Quote 0
            • K
              kcpoole
              last edited by

              @johnpoz:

              pfsense under diag, packet capture can do all the packet capture you need to do..

              If you need a host outside to confirm – just PM the info, happy to to do a test connection to it and tell you what I see active and passive what is being sent to the client, etc.

              I Did some testing and the IP is being rewritten as it is supposed to.
              Some of the Connection attempts i have made work for a moment or two but most just fail at the data connection and times out

              ken

              Screenshot.png
              Screenshot.png_thumb

              1 Reply Last reply Reply Quote 0
              • K
                kejianshi
                last edited by

                I'm confused.  FTP is dirt simple.
                So my first thought is what might you have changed that is breaking it?

                1 Reply Last reply Reply Quote 0
                • K
                  kcpoole
                  last edited by

                  @kejianshi:

                  I'm confused.  FTP is dirt simple.
                  So my first thought is what might you have changed that is breaking it?

                  As far as I can tell, Nothing has changed at my servers, The remote server, or the firewall. The Firewall was rebooted after power failure and then next time the users could not connect sucessfully and upload files:-(

                  just trying an inbound connection to my own FTP server while capture the traffic and this is the capture once already connected.

                  the 114 IP is my firewall wan address and 60.240 is my client here that I am trying to connect from.

                  it does not matter it seems whether I am trying to connect into my ftp server or out to an external one, the ftp connection is setup correctly but once data is to be tranferred it fails.

                  Ken

                  Screenshot-1.png
                  Screenshot-1.png_thumb

                  1 Reply Last reply Reply Quote 0
                  • K
                    kejianshi
                    last edited by

                    Are you using a static public IP or dynamic one?  Do you use a dynamic dns updater?

                    I'm wondering if its as simple as your IP changed.

                    Also thinking if its not, wipe the pfsense and reinstall then restore your config.

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

                      I don't see any data attempts in your post..  And where are you sniffing, see send fin,ack and then retrans it twice - I assume that is your wan..  So what does pfsense have to do with not seeing a a response and sending retrans?  Not like the answer is seen at the wan at pfsense?

                      In the first looks like see the syn from 182 to 114, and then 114 sending back syn,ack - and then sending it 2 more times.. because no answer?  That is on your wan is in not - so what does pfsense have to do with no answer from 182?

                      can you post up the sniff, so we can look at the details?  To me looks like you have problem outside pfsense.  If these sniffs are taken on the pfsense wan?

                      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
                        kcpoole
                        last edited by

                        @johnpoz:

                        I don't see any data attempts in your post..  And where are you sniffing, see send fin,ack and then retrans it twice - I assume that is your wan..  So what does pfsense have to do with not seeing a a response and sending retrans?  Not like the answer is seen at the wan at pfsense?

                        In the first looks like see the syn from 182 to 114, and then 114 sending back syn,ack - and then sending it 2 more times.. because no answer?  That is on your wan is in not - so what does pfsense have to do with no answer from 182?

                        can you post up the sniff, so we can look at the details?  To me looks like you have problem outside pfsense.  If these sniffs are taken on the pfsense wan?

                        Yes the sniffs are on the outside interface using pfsense to take them.
                        the last one posted was limited to a single IP and port 21 as there  is much other traffic to that host.

                        Happy to post the full sniff but how can i remove the password from it? i do nt really want to post the ftp details on the web

                        Ken

                        1 Reply Last reply Reply Quote 0
                        • K
                          kcpoole
                          last edited by

                          @johnpoz:

                          To me looks like you have problem outside pfsense.

                          I am wondering that myself. how can I prove or test that thought?
                          I am setting up another host on my network that is outside the pfsense and hope I can find the issue there.

                          Ken

                          1 Reply Last reply Reply Quote 0
                          • K
                            kcpoole
                            last edited by

                            Does anyone have an ftp server I can test uploading to?
                            The one my client is trying to send to does not work for me, I have my own that i use at my home and that works fine :-(

                            TIA
                            Ken

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

                              Valid point with the passwords - which is why there are anon tools for sniffs ;)

                              You could use http://www.tracewrangler.com/ to remove the passwords..

                              So see my first sniff where there billy password sent to ftp.microsoft – You add an anon task, set everything to passthrough except the text part.  You put in the original and what you want to replace it with.  See 1st attachment

                              You run the task, and then the new pcap it creates doesn't have your password in there ;)  But all the other info is in tact for looking at what could be wrong..

                              You can anon other stuff as well like IPs, etc.  Don't go all crazy on it, it can make it difficult to spot issues if too much manipulation is done.

                              replacedcopy.png_thumb
                              replacedcopy.png
                              anonpasswordsout.png
                              anonpasswordsout.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
                              • K
                                kcpoole
                                last edited by

                                Thanks John for the link to the anonymizer

                                I have rerun the capture and attached it below
                                Any help to work out why it is failing will be great.

                                note: I have appended .txt to the end of the file so i can upload.

                                Thanks
                                Ken

                                [Capture - FailFTP_anon.pcapng.txt](/public/imported_attachments/1/Capture - FailFTP_anon.pcapng.txt)

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

                                  well clearly this is wrong.

                                  So see the port command to IP 114 port 52030

                                  Why is it trying to go to IP 170?

                                  And where is this address coming from - see second image.

                                  wrongip.png
                                  wrongip.png_thumb
                                  wrongaddress.png
                                  wrongaddress.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
                                  • K
                                    kcpoole
                                    last edited by

                                    Ok i did not see them at all.
                                    the Address 114 is my own server and the server on 182.50.153.244 is the host I am trying to get to
                                    I have no idea what the other IP addresses are and what they are doing in the converstaion. thanks I will have to investigate where they fit inot it.

                                    Ken

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

                                      well that is not the capture you gave then..

                                      This is 170 talking to a 88, that seems to report its IP address is 182 in the banner.

                                      The port command yes tells this server 88 hey come talk to 114 on port 52030 for the data connection, but the SYN from 20 source port to 52030 is going to to 170.  Which yeah never answers..  You see the retrans, and you see it tell it hey come talk to more ports as well where the port commands are 114, but traffic is to 170.x.x.x

                                      You have dual wan connection on this pfsense?

                                      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
                                        kcpoole
                                        last edited by

                                        Nope only single wan network connected

                                        is there any possibility that somehow the port 20 traffic redirected or hacked?

                                        What does the handling of the traffic on port 20 ?

                                        Ken

                                        1 Reply Last reply Reply Quote 0
                                        • K
                                          kcpoole
                                          last edited by

                                          @johnpoz:

                                          well that is not the capture you gave then..

                                          When i compare the non anoymised capture it show the correct IP addresses wher the one I posted has different IPs in it !

                                          Sorry but the process must have changed them all. I will repost the other.

                                          Ken

                                          1 Reply Last reply Reply Quote 0
                                          • K
                                            kcpoole
                                            last edited by

                                            Okay sorry but In the original file i uploaded i anonymized the IP addresses too by mistake
                                            Redid the process and here is the correct file

                                            Ken

                                            [Capture - FailFTP_anon.pcapng.txt](/public/imported_attachments/1/Capture - FailFTP_anon.pcapng.txt)

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