SSH domain name misdirection

[Haines Brown KB1GRM ET1 <brownh%historicalmaterialism.info@localhost>]

My aim is to set up a ssh2 client on a laptop and use it to access via 
Internet an account located on a ssh server machine on a home LAN. I'm 
running linux debian.

I can ssh from one machine to another within the LAN without any 
problem:

        $ ssh user@hostname

However, my aim is to have a host on the LAN to be the server for the 
client laptop when it is not on the LAN, but is remote. To set this up 
and test it out, I've been trying to establish a ssh connection 
between machines on my LAN by using the domain name:

	$ ssh user@domainname

The result is a permission denied message from the nameserver provided 
by my web hosting service. It seems that the name server directs the 
ssh login query to my website, which has the same domainname as my 
machines, and the website does not recognize the password. Or at least 
this is my guess. 

How do I get the nameserver to direct login queries to my local router 
so that it then redirects the query to the proper machine on the LAN. 
I have the (dynamic, I assume) IP address for my router assigned to it 
by my ISP. I've tried without luck: 

  	$ ssh user@routerIPaddress  

I don't here provide specific information because my question is a 
general one about how one sets up a situation such as I describe.

Haines Brown