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Re: [TCLUG:12739] connecting to wu-ftp



Timothy Wilson [wilson@visi.com] wrote:
> Hi everyone,
> 
> I'm experiencing some weirdness trying to connect to my server via ftp. It
> seems like I have trouble with ncftp, "regular" ftp works, and it appears
> inaccessible from a browser. I'm thinking it has something to do with
> "passive" mode. Can someone explain what passive mode is and whether I
> should or shouldn't be using it? I've read some FAQs, but haven't found a
> situation that matches mine.
>

The normal ftp protocol uses 2 different connections, one for data (port 20) and the other for commands (port 21). The command connection is first established by the client to the ftp server on port 20. When a get/put is executed, the server opens a connection back to the client to a random high-port on the client machine. Now there are 2 connections going. This is called active ftp. Passive ftp uses the 1 connection for both communication and data.

As for your problem, I have no idea. Normally active mode has problems because of that 2nd connection getting blocked somewhere. (firewall, etc.) Are you getting anything in your logs? Maybe try a tcpdump...


 
> -Tim
> 
> BTW, the server is ftp://science.sibley.isd197.k12.mn.us/
> 
> --
> Tim Wilson        | Visit Sibley online:         | Check out:
> Henry Sibley H.S. | http://www.isd197.k12.mn.us/ | http://www.zope.org/
> W. St. Paul, MN   |                              | http://slashdot.org/
> wilson@visi.com   |   <dtml-var pithy_quote>     | http://linux.com/
> 
> 
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-- 
Clay Fandre
cfandre@maddog.mn-linux.org
Twin Cities Linux Users Group
http://www.mn-linux.org