Downloading error when connecting through SOCKS4 / SOCKS4a proxy

[fire-lizard]

FTP OS: Windows

FTP Server: Reproduced on WindowsServerIIS, XLight, EFT and FileZilla

Computer OS: Windows

FluentFTP Version: 38.0.0

When I am trying to download file through SOCK4 / SOCKS4a proxy I get the error: Failed to get the EPSV port from: 442629 Please note that 442629 is the file size, when I try to download different file, I got different number here, which is also a file size. When I download through SOCKS5 or without proxy at all, everything is ok. Also it works ok with TitanFTP.

Logs :

# Connect()
Status:   Connecting to ***:1080
Response: 220 Xlight FTP Server 3.8 ready...
Status:   Detected FTP server: XLight
Command:  USER ***
Response: 331 Password required for nuser
Command:  PASS ***
Response: 230 Login OK
Command:  FEAT
Response: 211-Features supported
Response: REST STREAM
Response: EPRT
Response: EPSV
Response: SIZE
Response: MDTM
Response: MFMT
Response: AUTH
Response: PBSZ
Response: PROT
Response: MLST type*;size*;modify*;
Response: MLSD
Response: 211 End
Status:   Text encoding: System.Text.ASCIIEncoding
Command:  SYST
Response: 215 UNIX Type: L8
Status:   Listing parser set to: Machine

# GetFileSize("ValidFeed.xml")
Command:  SIZE ValidFeed.xml
Response: 213 442629

# Download("ValidFeed.xml")

# GetFileSize("ValidFeed.xml")
Command:  SIZE ValidFeed.xml
Response: 213 442629

# OpenRead("ValidFeed.xml", Binary, 0, 442629)
Command:  TYPE I
Response: 200 Type set to I.

# OpenPassiveDataStream(AutoPassive, "RETR ValidFeed.xml", 0)
Command:  EPSV
Response: 229 Entering Passive Mode (|||50312|)
Status:   Connecting to ***:1080
Command:  RETR ValidFeed.xml
Response: 150 Opening BINARY mode data connection for ValidFeed.xml (442629 bytes).
Status:   Disposing FtpSocketStream...

# OpenRead("ValidFeed.xml", Binary, 442635, 0)

# GetFileSize("ValidFeed.xml")
Command:  SIZE ValidFeed.xml
Response: 226 Transfer complete (7025.857 KB/s).

# OpenPassiveDataStream(AutoPassive, "RETR ValidFeed.xml", 442635)
Command:  EPSV
Response: 213 442629
Status:   Disposing FtpSocketStream...

[robinrodricks]

Since you contributed SOCKS4x support into the library you would be the best person to debug this.

[fire-lizard]

Looks like error is gone for Windows IIS and FileZilla after these code changes (still remains for XLight though):

https://github.com/robinrodricks/FluentFTP/pull/893

[robinrodricks]

Please check if this works for you:

https://www.nuget.org/packages/FluentFTP/37.1.2

[fire-lizard]

I have checked it and confirm that it fixed problem for WindowsIIS and FileZilla. Unfortunately there is still Failed to get the EPSV port from: [file size] problem with XLight.

[robinrodricks]

I used your same code, just kept it for proxy and not for normal FTP client since I'm not sure if it will mess something up.

[fire-lizard]

Reproduced issue (using the latest version of FluentFTP) on EFT server as well

[robinrodricks]

Did it work with your fork? (As I said, I used your code)

[fire-lizard]

Yes, it did. It fixed issue with download restarting (for Windows IIS and FileZilla), but not "Failed to get EPSV port [file size]" issue (for XLight and EFT)

[robinrodricks]

I am in process of creating a new test suite which uses dockerized FTP servers. Can you recommend any dockers for these FTP Servers which you are testing OR any of the proxies?

[fire-lizard]

I am using 3proxy (https://github.com/3proxy/3proxy) as proxy server (supports both SOCKS4 and SOCKS5). There is my config for 3proxy:

auth none
log
socks

I don't use any dockers, I am using VMware Workstation 16.2.3 with Windows 11 on it, where I installed Windows IIS FTP, FileZilla, TitanFTP, XLight and EFT.

[fire-lizard]

Looks like I fixed this bug for XLight and EFT too. Please see pull request #947