# ssh port forwarding



## Abstract (Nov 25, 2010)

Hi Everyone,

I did setup port forwarding on the ssh server. It can forward pop/smtp/ftp connections and I have a proxy server running on my freebsd server to handle http and https connections. I use it when I'm traveling and want to connect from a hotel. 

Everything works fine except for one annoying behavior in the ftp uploads and download of bigger files. During the download or upload of these bigger files the process stops every time when 64kb is sends. The ftp client reports the transfer is complete, it looks like the connection closes and is rebuild again. After that an other 64kb is send. The ftp clients tells me again the transfer is complete and it starts to reconnect again. This continues tills the file is transferred. 

You can imagine this reconnecting all the time takes up lot of time which makes uploads/downloads of bigger files long and slow. 

I'm using putty as port forwarder. Total commander as ftp client with sock4 to connect to the port forward on the ssh tunnel. With sock5 I have the same problem. 

Does anyone has a clue why this happens? 

Best Wishes


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## SirDice (Nov 25, 2010)

Hmm.. I'm using something similar, using putty to forward over ssh and I've never had any connection issues.
Just to rule out client/server errors, did you try a different ftp client and/or ftp server?


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## Abstract (Nov 25, 2010)

I tried both things, but every time I'm having the same problem. If your workstation is windows could you tell me which ftp client you're using? To enable dynamic port forwarding I use the ' -D 21' option when starting up putty from the command line.


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## SirDice (Nov 26, 2010)

I don't use FTP. But I do download large files over HTTP. I'll see if I can FTP something today.

And you don't have to use -D21. A higher port will do just fine. I use -D8080.


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## Abstract (Nov 27, 2010)

Hi SirDice, 

You have made my day!! I though why not give it an try and change -D21 to -D8080, to my surprise it worked!
It just uploads the file without any problem, switching back to -D21 the problem is appearing again. Also other
ports like 8081 works perfectly now. It seems the problem lays in forwarding port 21 for ftp in my situation. 
Thank you, solutions are sometimes so simple!


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