help with Thomson st780

[firesteel]

I'm trying to get HFS to work with a Thomson st789 dsl modem + router.
It fails the self test, but I can access it from another computer in my LAN.
One maybe complicating thing is that I'm running apache on this machine, and have it serving on 3 IPs.
My IP addresses look like:
192.168.1.x
192.168.y.a
192.168.y.b
192.168.y.c
Apache is configured for the 192.168.y ips. plus localhost.
I've followed the directions at portforward.com for this router using a number of different port numbers. I forward it to the
192.168.1.x IP. I've also tried totally disabling the firewall in the st780, still fail the self test.
Will the test fail if for example it can forward to one of the ips, but not to one of the others?
But I'm thinking that if I can access HFS from another computer on the lan, that everything on this machine is OK. That is, there's no firewall problem, the other IPs aren't interfering, and HFS is set up correctly, que no?.
So it has to be that it's either not getting through my ISP, or not getting through the modem/router, right?
Is there some kind of tool that will tell me what traffic reaches the internet side of the modem/router?
You know I'm just trying to get a big file to a friend and there's other ways to do it but I like this HFS program and I want to get it to work.

[rejetto]

the self test "just" simulates a request from a browser over the internet.
the test fails -> you are not serving over the internet.
since it is working fine in your LAN, than it may be a routing problem.
anyway, did you get any other server software working on the same machine?

[firesteel]

> did you get any other server software working on the same machine?

Not as far as serving pages outside the LAN. Haven't tried it, I'm using it for development work and haven't wanted to mess with it.

[firesteel]

OK, I tried it. Now I'm more puzzled. I port forwarded port 80 on the router, and that allowed me to see documentroot from another computer on the LAN. I thought port forwarding had to do with "making a hole through the firewall," and I thought the firewall is between the internet and all the computers on the LAN. But that conception doesn't fit these facts. The port forwarding did something between two computers on the same LAN.

Besides that, with port 80 forwarded, I can't see documentroot outside the LAN. That means that the ISP is blocking it?

[rejetto]

many ISPs do it
consider this
inside out -> you are connecting to a computer on the internet, its address is specified, nothing else to worry
outside in -> someone is connecting to a computer in your LAN, he specified your router address (external), so the router needs to know which exact PC it should forward the request

a correct forwarding in a single-router enviroment should be enough to make it all work, assumed that no other firewalling is interfering.