FTP Connection Difficulties?

[ElijahBaley]

Hi

I have setup an FTP box within a private LAN and mapped a public IP address through the firewall to it.

The FTP server does not have public access and is accepting connections on a non standard port.

I can connect and transfer files from within the LAN and also from my home PC (outside the LAN) - but my customers are unable to make a clean connection.

When they try to connect they appear to authenticate ok, but do not get a directory or file list displayed. They have tried several different client programs but can not 'see' any files?

I have checked and checked again passwords and permissions, has anyone got any ideas as to what could be going on?

Thanks



..EB


"Smoke me a kipper, I'll be back for breakfast!"

"Captain A.J. Rimmer, Space Adventurer!"

 

[Grenage]

FTP has two available modes, Passive and Active.

One uses port 21(default) for the handshake but uses port 20(default) for data transfer.

The other uses a random port of >1024.

If port 21(or whatever you are using instead) is enabled for customer access, is 20(or whatever is being used isntead) also accessible?

For more information on the FTP protocol, try here:

http://slacksite.com/other/ftp.html

 

[ElijahBaley]

Looks good, I think that my problem is related to the protocols unusal use of two TCP ports, the document that you recommended looks very good, so Im going to wade through it now.

Thanks very much

..EB


"Smoke me a kipper, I'll be back for breakfast!"

"Captain A.J. Rimmer, Space Adventurer!"

 

[bcastner]

While written in a Linksys context, the following articles are universal in applicability:

http://www.broadbandreports.com/forum/remark,1381832;root=equip,16;mode=flat

And MTU issues:

http://www.broadbandreports.com/forum/remark,1700907~root=equip,16~mode=flat

 

[bierhunter]

I can connect and transfer files from within the LAN and also from my home PC (outside the LAN) - but my customers are unable to make a clean connection.

You say that you can connect from outside of your LAN, but your customers cannot. Therefore, your ports, NAT, etc, and such should be ok. Otherwise, you would not be able to connect.

The question I have is "What are your customers doing different?"

Why can they not connect from the outside, and you can? That's where I would start looking.

My first suspiscion is that you stated your server uses a non-standard port. Do your customers have their FTP clients configured properly?

BierHunter
CNE, MCSE, CCNP

 

[ElijahBaley]

Sorted!

Thanks for all your help, I had to configure my Firewall to allow passive conections. I think that the reason that I was able to connect from home, while other people outside of the office were unable to connect was because my software firewall autoconfigured to allow an acitive connection from the server.



..EB


"Smoke me a kipper, I'll be back for breakfast!"

"Captain A.J. Rimmer, Space Adventurer!"