[IPTABLES] My computer SHOULD be reachable...

Do you have a globally routable IP on your machine?

To confirm: Is your ADSL modem bridging, or other wise routing globally routable IPs to your computer?

We need to know more about your configuration before we can really say.

Grant. . . .

Something on the line definitely *is* filtering.

Yours, VB.

Are you sure you're using an ADSL modem (which exposes your interface on the Internet) and not some kind of ADSL Router?

Routers need to have reverse NAT enabled, in order to pass outer requests to your computer, otherwise they just drop the incoming packets that are unrelated to already established connections.

Several possibilities come to mind:

1. The person at your ISP is lying.
2. The person at your ISP doesn't know, so he/she gave the answer he/she thought you wanted to hear.
3. Your modem *does* have filtering capabilities.

-RW

My ISP modem has a firewall that you can disable or enable. And a port forwarding control which requires that you enter your IP in a form. It actually has a webserver that you connect to with a browser. I had to get the password from tech support. If port forwarding isn't configured properly and enabled (by checking a box), you won't get any connections from the net. The firewall could cause problems, too.

You probably don't have the same ISP, but something similar could well be going on.

Most ISPs block a lot of ports below 500. I always choose one over 1000 if possible.

Sid

At work I had some of the most difficult times when trying to solve problems before verifying what the customer said.

He may be using a router, not a modem, and he may just have to enable port forwarding on it.

I'm 100% sure I'm using a modem, not a router. The modem is not even user-configurable (it would need a password that only the manufacturer knows and won't disclose).

I've had this modem for 5 years and I know I used to be able to open ports on this computer just by telling iptables what to let in.

No, I have a 192.168.1.x/24 address for the ethernet interface, which is on the same subnet as the modem (the modem is 192.168.1.1, LAN-side).

Internet-side, my ISP leases my modem a variable IP that is globally routable.

I see, forgive my allegation. Is the IP address of your ppp interface equal to the one that is detected by the online scanning tools?

My ethernet interface has an internal IP (192.168.1.x/24) on the same subnet of the modem's internal IP. Basically it's a bridging modem. I'm not using PPP.

Were I in your shoes, I'd try the following

- set eth0 to your public IP address (not some private 192.168.x.x)

- get the password of your bridge/modem/router/whatever from you ISP

- use traceroute to find out if there are private networks before the Internet

I leave the matter in more experienced hands, as I am not very experienced with these kind of bridges (assuming a bridge this is). Good Luck.

-- enos76