FTP Client problem



  • Hi,
    I have a problem accessing ftp servers, only from clients that are behind pfsense, after logging in and running "ls" command I can not see the list of files.
    This problem only occurs with the Microsoft ftp client (I tried with Windows 2012, 2016) while with filezilla I have no problems.
    Thanks.


  • LAYER 8 Global Moderator

    ms ftp client only supports active mode. If you want to use active mode ftp with client behind pfsense to ftp server outside pfsense you need to install the ftp package and configure it. Its called FTP_Client_Proxy in the packages.



  • Hi, the ftp server that I try access support passive mode (and with filezilla I connect in passive mode), I still need to install the package FTP_Client_Proxy ?
    To these ftp servers, from clients that are not behind pfsense, I can log in with ms ftp client with success.
    Thanks.


  • LAYER 8 Global Moderator

    Again the ftp client (ftp.exe) in windows only supports ACTIVE... If you want to use active on clients behind pfsense then you need to install that package..

    If your clients use passive then no you do not need the package... Understanding how ftp works is step 1 ;)
    http://slacksite.com/other/ftp.html
    Active FTP vs. Passive FTP, a Definitive Explanation

    That your still using ftp at all would be the question I would be asking yourself... It should of died off 10 years ago... Why can you not use sftp?



  • Hi,
    unfortunately, the ftp servers to which I have to connect are not managed by me, I use the client part.
    I attach image related to the error I have on the ftp client.
    The same connection, from the same ftp client to the same ftp server, from a PC that is not behind pfsense works well.
    Thanks.0_1548865469169_ftp4.JPG


  • LAYER 8 Global Moderator

    Dude how dense can you be?? the ftp.exe in pfsense does NOT support passive... If you want to use active ftp client behind pfsense you need to install the ftp package!!

    They might have a passive cmd - IT DOESNT WORK!!! windows ftp.exe ONLY supports active!!!



  • Hi,
    so an ftp client that is behind pfsense and needs to access an ftp server that only supports passive mode, will it never work?
    did I get it right ?
    Thanks.


  • Netgate Administrator

    No.
    Passive FTP will work fine with the client behind pfSense without the proxy package.
    Active FTP requires the client proxy package.

    Since the Windows ftp client apparently only supports active mode you need the client proxy package.

    https://www.netgate.com/docs/pfsense/nat/ftp-without-a-proxy.html#client-behind-pfsense

    But are you sure those servers don't support encrypted mode? If they do you just switch to that.

    Steve


  • LAYER 8 Global Moderator

    So which is it you do not read english, or your trolling... Have been over this multiple times now!!

    Please what part is unclear here

    Again the ftp client (ftp.exe) in windows only supports ACTIVE... If you want to use active on clients behind pfsense then you need to install that package..

    If your clients use passive then no you do not need the package...

    And before that how can this be clearer

    ms ftp client only supports active mode. If you want to use active mode ftp with client behind pfsense to ftp server outside pfsense you need to install the ftp package and configure it. Its called FTP_Client_Proxy in the packages.

    Your ftp.exe command tells the server hey lets do passive - and the server answers back ok, lets do passive - connect here on this port... The problem is the ftp.exe from windows will not do passive... You have to use the ftp package in pfsense to allow for active connections from clients behind pfsense because the firewall needs to open the port back to the client..



  • Hi,
    it does not work either in active or passive mode.
    I installed the ftp proxy package and I indicated the LAN as an interface to be used (I have not modified any other parameter) but also in this way I always have the same problem.

    I'm sorry if I did not understand what you told me but I can not understand where I'm wrong.
    Thanks.


  • Netgate Administrator

    If you set 'Log Connections' in the proxy settings do you see firewall log entries for it?

    Do you see blocked traffic from the FTP server?

    You might try using a different FTP client as a test here such as Filezilla. That will show you exactly what it's doing.

    Steve


  • LAYER 8 Global Moderator

    is the checkbox set to move it up the higher on the rules?

    Here just tested this

    C:\WINDOWS\system32>ftp speedtest.tele2.net
    Connected to speedtest.tele2.net.
    220 (vsFTPd 2.3.5)
    200 Always in UTF8 mode.
    User (speedtest.tele2.net:(none)): anonymous
    331 Please specify the password.
    Password:
    230 Login successful.
    ftp> ls
    200 PORT command successful. Consider using PASV.
    150 Here comes the directory listing.
    1000GB.zip
    100GB.zip
    100KB.zip
    100MB.zip
    10GB.zip
    10MB.zip
    1GB.zip
    1KB.zip
    1MB.zip
    200MB.zip
    20MB.zip
    2MB.zip
    3MB.zip
    500MB.zip
    50MB.zip
    512KB.zip
    5MB.zip
    upload
    226 Directory send OK.
    ftp: 183 bytes received in 0.02Seconds 11.44Kbytes/sec.
    ftp>
    

    active works just fine with windows ftp client behind pfsense..

    You can see where its allowed through the firewall with these rules

     	Jan 30 12:28:54 	► LAN 	(@0) 	90.130.70.73:20		192.168.9.100:55659		TCP:S
    	Jan 30 12:28:54 	WAN 	(@0) 	90.130.70.73:20		192.168.9.100:55659		TCP:S 
    

    Here doing it again with sniff..
    0_1548873396618_controlanddatasniff.png

    Notice the port command sent is my machine rfc1918 IP, the ftp client changes that to my public IP, and if you do the math on the command (217*256)+148 = 55700 which is the port the data channel is sent to..



  • @stephenw10
    Trace: CControlSocket::SendNextCommand()
    Trace: CFtpLogonOpData::Send() in state 0
    Stato: Risoluzione dell'indirizzo IP x.y.eu in corso
    Stato: Connessione a x.x.x.x:21...
    Stato: Connessione stabilita, in attesa del messaggio di benvenuto...
    Trace: CFtpControlSocket::OnReceive()
    Risposta: 220 Microsoft FTP Service
    Trace: CFtpLogonOpData::ParseResponse() in state 1
    Trace: CControlSocket::SendNextCommand()
    Trace: CFtpLogonOpData::Send() in state 5
    Comando: USER pippo
    Trace: CFtpControlSocket::OnReceive()
    Risposta: 331 Password required
    Trace: CFtpLogonOpData::ParseResponse() in state 5
    Trace: CControlSocket::SendNextCommand()
    Trace: CFtpLogonOpData::Send() in state 5
    Comando: PASS **********
    Trace: CFtpControlSocket::OnReceive()
    Risposta: 230 User logged in.
    Trace: CFtpLogonOpData::ParseResponse() in state 5
    Trace: CControlSocket::SendNextCommand()
    Trace: CFtpLogonOpData::Send() in state 9
    Comando: OPTS UTF8 ON
    Trace: CFtpControlSocket::OnReceive()
    Risposta: 200 OPTS UTF8 command successful - UTF8 encoding now ON.
    Trace: CFtpLogonOpData::ParseResponse() in state 9
    Stato: Accesso effettuato
    Trace: Measured latency of 5 ms
    Trace: CFtpControlSocket::ResetOperation(0)
    Trace: CControlSocket::ResetOperation(0)
    Trace: CFtpLogonOpData::Reset(0) in state 14



  • @johnpoz I do not work, when I run "ls" I have the error message that I attach0_1548873937691_ftp error.JPG


  • LAYER 8 Global Moderator

    I don't see any port or pasv command sent in that log... Just sniff on the wan and lan of pfsense while you doing this so you can validate what is happening... ftp control is in the clear so as you see above you can see exactly what is sent by the client in the control channel. If when you sniff on the wan side you will see the ftp package change your port command to your actual public IP

    Is pfsense behind a NAT? Not going to work if behind a NAT..

    Is the wan of pfsense on a public IP? Sniff while you do that test of ftp to speedtest.tele2.net

    So we can see exactly what is happening.



  • yes, the computer is behind a NAT, it has a private IP address.


  • LAYER 8 Global Moderator

    NO pfsense is its wan a rfc1918 or the is it public?



  • @johnpoz on pfsense I have wan interface e lan interface, on wan interface I have an public IP address.


  • LAYER 8 Global Moderator

    Like I said do a simple sniff.. And you can see exactly what is going on..

    Here sniff (diag, packet capture on my wan) you can see my login on port 21... See where the PORT command gets changed to my public IP..

    0_1548874506740_sniffonwan.png

    Then here comes the data connection to the port in the the port command

    0_1548874537590_datasniffonwan.png

    (200*256)+175 = port 51375



  • This post is deleted!


  • @johnpoz sorry I do not know how to capture the really useful information, in the figure I sent I deleted the private IP address that is shown in the capture0_1548881523155_Cattura.JPG


  • LAYER 8 Global Moderator

    Dude are you hiding a 10.x.x.x address? Why??? They are private and do not route on the internet... That info is useless to anyone knowing what it is.. Its like telling you I live in the US.. or the planet Earth.. Notice how I didn't hide my 192.168.9.100 address ;) You can capture the info right on pfsense.. diagnostic menu packet capture.

    Do the capture on your WAN interface so we can validate its getting changed to your public wan IP.. Then just download the capture and open with wireshark.

    In wireshark just right click on say the syn of the control channel and say follow stream.

    BTW, I am a mod so I can see your deleted post ;) There is ZERO reason to hide 10.0.0.18.. You need to validate that gets changed on your WAN.. This is why you need to do the sniff on the WAN of pfsense to validate your ftp package is working.

    here
    0_1548883707284_packetcapture.png

    Then download and open with wireshark
    0_1548883729585_openwithwire.png



  • @johnpoz here is the log, I hope it contains useful information.
    Thanks.0_1548927500486_cattura1.PNG


  • LAYER 8 Global Moderator

    So he sent data connect to port 51069, which is correct per the PORT command.. (199*256)+125 but no answer..

    Did the package not create the firewall rule? Did it not get placed at the top like I asked before

    0_1548928001120_ftpproxy.png

    Did the pfsense forward it, but your client didn't answer? Sniff on the LAN side now when you do the test.. We can see from the sniff that the PORT command was changed to your public IP with that 167.x.x.x

    So yeah its very useful information.

    What are your firewall rules on your WAN? Are you running packages like Snort or Pfblocker?



  • @johnpoz I have checked the "Early Firewall Rule" but I do not see any new rules in either LAN or WAN.
    In Rules -> WAN I have only the default rules and I do not use Snot or similar packages.
    Thanks.1_1548929897417_Cattura2.PNG 0_1548929897416_rules WAN.PNG


  • LAYER 8 Global Moderator

    Well from your sniff you can see that the data connection was sent on by pfsense - so its doing EXACTLY what it is suppose to do... Yet your client is NOT answering...

    (193x256)+69 = port 49477

    You see all the SYN to your clients IP 10.0.0.18... Why does it NOT answer? Host firewall?

    0_1548930544209_clientnotanswer.png

    So why would your client not answer. I can see that the port is not set to 20 as source.. But it was on your sniff on WAN, Its possible your client WANTS that... Click this in in the package

    0_1548930782828_portto20.png

    Now test it again.. Bet you works now.



  • @johnpoz with WIndows Firewall disable the ftp problem did not occur !
    there was no need to check "rewrite source ..".
    On the windows firewall do I have to enable traffic on high ports?
    thank you


  • LAYER 8 Global Moderator

    You would need to enable the application ftp.exe in the firewall most likely.. I don't use windows firewall - I have it disabled on all my windows boxes.. They all reside on a SECURE trusted local network that is isolated from all the iot gear and and anything that gets touched by the outside.. No reason to run it.. Leave it off locally - but set to say if my wife takes laptop out to some hotspot it would be on, etc.

    But yeah your not going to know what port the client tells the server to connect to... This is the reason for the ftp helper package. The firewall needs to view the control channel info.. And it needs to do 2 things, it needs to change the clients port command from the rfc1918 address to what the public IP is.. And it needs to open a firewall rule/port forward for the data channel traffic the server will send to that IP and port so it gets back to the client.

    Your host firewall would need to make sure it allows for what looks like unsolicited traffic from the server when it starts the data connection in active mode.

    Your much better off using a client that does passive.. Since in passive mode both the control and data channel are initiated by the client.. So no need for the ftp helper package, and no need for inbound firewall rules, etc.


  • Netgate Administrator

    Nice.

    Interesting that it behaved differently with a different router. I imagine the windows firewall saw it as a new network.

    Steve


  • LAYER 8 Global Moderator

    yup its quite possible that it was turned off on the other network, and when put behind pfsense it switched to public, etc.



  • @sasa1
    Hi.

    Just create Alias with your ftp servers IPs\names and then make fw rule on LAN when this Alias would be in Dst with needed ftp ports. Set this rule first by order.


  • LAYER 8 Global Moderator

    huh? Dude you might want to actually read the thread before responding ;)


  • Netgate Administrator

    Um... yeah that would not have helped at all in this case. Traffic to any ftp server was already allowed and passing.

    Steve


Log in to reply