Flashfxp with socks bug

[WinEggDrop]

The bug Is:
As flashfxp connected to the socks(sock4 or sock5),and the socks connected to the remote ftp server and returns the banner to flashfxp(the banner is usually 220 XXXXXX Is ready),but flashfxp sends nothing back to the sock after then(I sniffer the package,and sure flashfxp does receive the banner,and it should send USER YYYY to login,but it doesn't).

This only happens the banner is only one line,if the banner is over one line such as "220- XXXXXX is ready\r\n220 please dont' using more than 2 threads to connect\r\n",flashfxp will work fine.
I do test this with all flashfxp 3.0 Versions,cuteftp,ws_ftp as well.
only flashfxp has that problem,so it won't be the socks problem.

[bigstar]

What socks4/5 proxy software was used?

What ftp server software was used?

I've tested with several different proxies (WinProxy, Analog Proxy, Socks4 for linux) and FlashFXP works fine with them, Also with several different ftp servers (G6, ioftpd, Serv-u, glftpd, proftpd, warftpd)

My only guess is that maybe the line isn't ending with CR or LF which is required to determine the end of the line.

[WinEggDrop]

ftp server is serv-u,and the sock5 proxy is antinat.I am sure the ending characters \r\n is sent to flashfxp(my sniff can get it,and I don't know whether flashfxp also gets it or not).By the way,I found another problem related to the above one.When flashfxp with socks proxy(antinat in my case),and as listing,if the result all comes in once(the entire files and directories list sent back to flashfxp),flashfxp is fine,but if the result comes in several times,flashfxp misses some bytes.
For example:the below is the sniffing result

The below line comes first:
drw-rw-rw- 1 user group 0 Jan 08 20:15 New

The rest come at once
drw-rw-rw- 1 user group 0 Jan 11 17:44 old
drw-rw-rw- 1 user group 0 Jun 05 03:09 [╫█╥╒╞¼]
drw-rw-rw- 1 user group 0 Jan 07 05:25 [╧▓╛τ╞¼]
drw-rw-rw- 1 user group 0 Jan 07 05:26 [╡τ╩╙╛τ]
drw-rw-rw- 1 user group 0 May 24 15:08 [╢»╫≈╞¼]
drw-rw-rw- 1 user group 0 May 25 00:22 [╖╕╫∩╞¼]
drw-rw-rw- 1 user group 0 May 28 03:42 [╛τ╟Θ╞¼]
drw-rw-rw- 1 user group 0 Jun 06 22:37 [┐╞╗├╞¼]
drw-rw-rw- 1 user group 0 Jun 06 22:48 [┐╓▓└╞¼]
drw-rw-rw- 1 user group 0 May 31 22:10 [╚╒║½╞¼]

but when flashfxp lists the result,the directory New(the line comes first) misses the characters "drw-rw-rw-",so in the flashfxp box,the directory 'New' Is neither a file nor a directory.

Again,this problem is only in flashfxp.If it's the socks proxy problem or ftp server problem,cuteftp or ws_ftp would probably have the same problem.

[WinEggDrop]

Ok,I finally figure out what goes wrong about flashfxp by coding a little sock5 proxy to test flashfxp.

after the authorization to the socks proxy,flashxp sends this request string to the socks proxy.
"5 1 0 3 14 50 49 56 46 51 56 46 50 49 55 46 49 52 50 11 199"
Let's look at the first 4 bytes:
5 is the sock5 version number
1 is the "CONNNECT" Method
0 is Reserved Byte
3 is Domain Name -> Here is the problem cause

First of all,the socks proxy and the ftp server are all IP V4 address, I don't know why flashfxp will use 3.Even it's ok to do so,
let's check the socks proxy reply.Since flashfxp's request uses 3,
so the sock proxy reply with "5 0 0 3 0 0 0 0 0 0" to flashfxp,the the above problem rises.If the sock proxy reply with "5 0 0 1 0 0 0 0 0 0",flashfxp will work fine.

cuteftp,ws_ftp and leapftp will only use "5 0 0 1 X X X....." in the request if both sock proxy and ftp server address are in IP v4 format.I doubt why flashfxp acts like that.The sock is ok to reply "5 0 0 1 X X X X ......",but if it does it,the sock proxy may have problem with sock udp protocol program.I have test over 5 different ftp clients,and only flashfxp's request is so different.

[bigstar]

I tested antinat Win32 version with FlashFXP and it appears to work perfectly, I was unable to determine any compatiblity issues.

I was unable to reproduce any of the problems you reported.

I forgot to ask, Are you using FlashFXP v3.0.2 build 1045?

I've never seen a socks proxy that couldnt handle a IPv4 IP address as the domain name and I've tested many proxies. Also in FlashFXP Socks 4 uses the IP address exclusively, Socks 4A will use the domain name.

[WinEggDrop]

It's not about sock4;it's sock5.see my post's socks version number.I know it's fine to put IPv4 address as domain name,but what's this for?only for fun?

[bigstar]

My socks4 comment was a side remark since you said both socks 4 & 5 didn't work.

I tested both socks 4 & 5 with antinat socks proxy.

Rather then using two different methods which basically do the same thing, it made sense to just use one method.