FTP Questions

[Roody]

okay couple of comments here. First, I have a friend who was thinking of setting up his computer as an FTP server, unfortunately his IP is dynamic. In order to access his FTP will he have to keep giving out his new IP as it changes or is there an easier way to deal with this?

Second, we were testing out his site today trying to get into his server. At first I couldnt get into it using CuteFTP. I tried it with CuteFTP on multiple computers and couldnt connect. Oddly enough when I tried it with WS_FTP I could get in. Any ideas on why his server likes one FTP Client and not another?

[cyberskye]

One was connecting in passive mode, one was connecting in active mode. The difference is which end (client vs. server) selects the port for data. The communication port is almost always 21. If both sides are effectively firewalled this becomes problematic...

[Roody]

ok so im not sure what this is telling me?

[cyberskye]

That's probably what's going on. You may need to change how cuteftp connects. I can explain how ftp works....

FTP works across two ports (command and data) and in one of two modes. The comm port is the one connected to by the client usually 21). Then things get a little different.

In active mode ftp: Once the client connects, it tells the server (via the comm port) which port to use for data. The server then connects to that new port at the client machine..

Security implication? The firewall on the client must be configured to allow incoming connections on all ports >1024.

Passive mode (PASV): (standard by the way for most browsers and other clients) Once the client connects then SERVER tells the client which port# to use to establish the data connection. The client still establishes the data connection, but has no control over which port will be used.

Security implication: Now the server must leave open a number of ports above 1024 to accept incoming data connections.


Firewalls (at least the kind you or I could afford) do not associate the two connections. In other words, thedata connection might look like an attack....

The server and the client must use the same mode to be successful.


Make sense? remeber, you asked...:)

Skye

A suggestion for you and your friend - and a more secure one at that?

http://www.networksimplicity.com/openssh/

This is a free, windows version of secure shell client and server. Made to replace ftp, rsh, rlogin, and rcp in the unix world. MUCH easier to protect and uses crypto. ftp passwords (the whole session actually) is sent in the clear - any snoop can capture the whole sessions.

[Roody]

thanks for that Cyberskye, i really appreciate the time you put into this. :)

[cyberskye]

Glad to help. Goes around and comes around :)

Cheers,

Skye

EDIT - as for the dhcp issue - search for "dynamic dns" on your favorite engine. This is a means of running public servers behind a dynamic ip.

[BlackSword]

Originally posted by cyberskye


http://www.networksimplicity.com/openssh/

This is a free, windows version of secure shell client and server. Made to replace ftp, rsh, rlogin, and rcp in the unix world. MUCH easier to protect and uses crypto. ftp passwords (the whole session actually) is sent in the clear - any snoop can capture the whole sessions. FYI looks like they just stopped supporting openssh today.

[cyberskye]

I guess I jinxed it :(

Let me check the developer's amazon wishlist and see if we can't get one more release out of him !

[Alex_Select]

http://www.no-ip.com/ will allow the following for free:


Use No-IP's FREE dynamic DNS solution to run a server at home even with a dynamic IP.


Our dynamic DNS update client tracks your changing IP.


Have a site with a long URL? Use a short host name to redirect to your existing site.

Plus they have pay serives...but for what you looking for would be perfect...they will even give you a free domain name...

Good luck...

[InTaH]

Another very popular program to try is www.dynip.com

I believe it has a trial period (30 days?), but it's the easiest to set up, and definately worth the couple of bucks/ month they're asking.

The Dynip client gives you a "username.dynip.com" static IP, and has a little program (that uses very little system resource) sitting in your tray which keeps track of your changing (dynamic) IP.

[Alex_Select]

and allows you to setup 5 hosts for free, and has more host names than just no-ip.com; then have a variety of ,com, .biz, .org, .us, .ca, etc....

[InTaH]

I just tried out No-Ip for the first time. Looks great :)
It actually looks better than my favorite - Dynip!

Thanks for the info.