[NTLUG:Discuss] Accessing a machine behind a router.

[Steve Baker]

Hi!

  I've always had a fixed IP address for my home machine in the past - 
and I always had a Linux box with two ethernet adapters as my 
firewall.   So if I needed something off my home PC when I was at work, 
I could (for example) ssh into the firewall box - then from there ssh 
into my internal network to get files and such.

  Now (as a temporary situation), I have a different setup where there 
is a LinkSys router getting it's address from my ISP via DHCP - and my 
PC hooked up to that - via DHCP (with the address allocated by the router).

  Let's suppose I know the currently assigned DHCP addresses of both the 
router and the PC - how the heck can I reach the PC from the outside 
world?   It's address is something like 192.168.1.2 and the router has 
some other address 66.xxx.xxx.xxx assigned to it by the ISP.   From the 
other side of the Internet, I can't "ssh steve at 192.168.1.2" - and 
(presumably) I can't ssh into the router and then get to my machine.  Is 
there some way to tell things like ssh, scp, and maybe occasionally NFS 
or my browser to go FIRST to 66.xxx.xxx.xxx and THEN to route to 
"steve at 192.168.1.2" ?

  Let's not consider HOW I know those two addresses - and let's not be 
concerned with security issues for the moment - I just can't get my head 
around how to route SSH-type commands through the router and onto the 
internal network.

Thanks!