Verizon DSL and FTP/SSH issues

Can somebody competent suggest finally something here ? (the web is full of unresolved complains about this).

PROBLEM

iMac, Leopard -FTP server activated, firewall completely disabled. No problem connecting to it from another machine on the same network using local network IP address (as listed in Apple sharing panel: "Other people can access your FTP server at ftp://192.168.1.x").

The problem is connecting to the server from OUTSIDE the local network (that is on the IP assigned to my machine by Verizon DSL modem/router combo) as this always fails with message: "Connection refused"

It is not clear to me what is refusing connection, the router, the mac itself or just the ftp server.

I set up port forwarding on the router (ports 20,21) per widely circulating instructions but that makes no difference whatsoever to my ability to connect to that server.

The situation is really confusing because a simple web check ( http://www.canyouseeme.org/) shows them open, fully accessible, but on the other hand when I do port scan in Network Utility on my mac I see them only open under local IP, external IP only allows 6 ports (telnet, http, http-alt, etc) open, and port forwarding on the modem makes no difference to what Network Utility reports as open on wide IP *.

I know that forwarding works on this Verizon modem from the fact that I was able to get my bittorrent client to work correctly (NAT problem) once I opened its port on the router. So I'm tempted to conclude that it is something on the mac that refuses. But what, firewall (shouldn't - it's disabled), the ftp server (unlikely 3rd party server "Pure FTPd Manager" shows exactly the same behaviour) ?

So who? And what to do?

Apple?

Mac OS X (10.4.7)

Posted on Oct 7, 2008 6:03 AM

Reply
16 replies

Oct 12, 2008 10:42 PM in response to Big Burro

Glad to hear your ssh/sftp/scp is working for you. Yeah, some home routers don't like you trying to use your external WAN IPA or external host name, if the source computer is on the same home network as is the target. Some do, some don't. Sounds like yours doesn't.

So now that that is working for you, are you familiar with all the idiosyncratic rules for handling filenames that have white spaces or other "special-meaning" characters in their filenames when dealing with the command line? Do you know how to tunnel afp through ssh so you can have your own "iDisk" of sorts (home computer remotely mounted on the desktop of your work or road computer)?

There are some things that I would urge you to look into doing in order to "harden" your ssh connection -- lots of internet evildoers out there, if their automated programs stumble across your IP address and see port 22 open, they will try to attack it using username/password dictionaries. They will coordinate attacks using zombied computers trying to get in to fool any protection mechanisms your router might have into thinking that it is not under attack.

You might find http://discussions.apple.com/message.jspa?messageID=8244911#8244911 helpful in both regards.

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Verizon DSL and FTP/SSH issues

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