ftp port 21 is blocked by my isp

Question

ftp port 21 is blocked by my isp

Hello,

Is there any way to work around port 21 that my isp is blocking for the built in ftp server in tiger?

I would like to share some rather large files with a client/friend as well as access my computer remotely for files and support while I am on the road.

I have heard of port forwarding and proxy servers but I do not fully understand how either works.

Can I get around port 21 so i can use my ftp server?

Any help would be most welcome.
I have tried for several days to get it working and then found out that Telus my isp is blocking ports 21, 80 and most likely many other server ports.

Cheers to anyone who can help.

Patrick

Posted on Sep 30, 2005 7:18 PM

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Answer 1

Sep 30, 2005 9:32 PM in response to Patrick Marchand

Is this an anonymous ftp server used by customers or yourself? what I do is utilize ssh for file transfers, the ports of which are totally configurable, although SBC does not block port 22, Iuse the default port 22.

Hope this helps. Good luck.

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Answer 2

Sep 30, 2005 10:50 PM in response to Scott Micciche

Hi Scott,

Thank you for your reply.

It is a server to be used by myself and the very occasional customer/colleage.
He will be using either a PC or a G3 with Mac OS 9.2 to either u/l or d/l files.

it is not an anonymous server.

How do you setup the ssh for file transfers? What is SBC?

Port 22... Can I simply tell the ftp server to listen on that port instead of 21?
How do I modify my host name to look for port 22 rather than the standard 20 or 21?

I am thinking that I will need to test for open ports that my isp may have left open. I fell they will not have left manyholes if they don't want people to run servers on their network. They have the ports opened up on a business plan but those plans start at 3x the cost of what what I have now.

The service is otherwise very good.

I hope that I am not asking too many questions.

Cheers,

Patrick

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Answer 3

Oct 1, 2005 9:24 AM in response to Patrick Marchand

SSH is apple's: "Remote Login" under the system prefs/Sharing. To utilize ssh you can use a command line like this:

scp file.name user@host:/home/userdirectory

You will be prompted for a password, but it is never sent in the clear, very secure. The default port for ssh is 22 and most ISP support that port usage.

SBC is a Western state telecommunications company with a large DSL customer base. I personnally wouldn't use ftp because of the chances of your passwords being sniffed.

You can go into the System Preferences/sharing and turn on the "remote login" and practice on your own local network. You will not see a daemon process running if you have panther or tiger as they are controlled by xinetd and launchd respectively.

Let me know if you need more help and I'll guide you through setting it up.

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Answer 4

Oct 1, 2005 1:14 PM in response to Scott Micciche

Hi Scott,

OK. so now I am more confused?

I used JellyfiSSH to log in and it opened the terminal app.

I have tested on my local network, but what do I do once I am in the terminal app? Will I be able to get back to a nice GUI or browser?

Will I be able to isolate my customer to a single folder?
Will he have to use a SSH like Putty on the PC?

Thanks again for your help with this.

Patrick

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Answer 5

Oct 1, 2005 4:06 PM in response to Patrick Marchand

The built-in FTP service in OS X is coded for ports 20-21 and can't be changed from the GUI. However, I assume it has it's own configuration files which could be changed using Terminal to use a different port.

Another, and far easier method would be to use a different FTP server, there are some commercial, and open source FTP servers available for OS X.

ProFTP, and CrushFTP, come to mind right away. And of course you could use your iDisk if you have a .mac account to share files with others.

Tom N.

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Answer 6

Oct 26, 2005 4:44 PM in response to Patrick Marchand

I do not mean to barge into the conversation, but I would like to throw my 2 cents in.

There has been alot of "urban legends" around the blocking of ports by ISP' s. I see it on chat boards, etc.

Did you have verbal confirmation by someone relevant from the ISP that port 21 is blocked? I have seen very few mainstream ISP' s that actually do this. Most of the time it is a router/firewall configuration issue.

I would do take a "legal approach" if indeed they are blocking port 21. Reason being is that as a consumer you have an "expectation of service" [In this case the internet access] and the ISP is breaching that confidentiality by limiting the functionality of your service. This is anti-consumer.

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