No, this is clearly not related with a defective router. At home, I have US Robotics 9108---must be more than 10 years old, an unbelievable workhorse! And at the workplace, the router is a ZyXEL P-660HN-F, one of more recent make.
Perhaps I did not explain the problem very well in the first post.
All users, whether on the WAN or LAN side put the text: http://my.domain.name.web.site.com/
in their http client (web browser) location/address text box. Their client name resolver module then connects to the DNS server, and eventually the DNS server network learns that the name belongs to DynDNS.org and the name resolution response comes back from DynDNS.org of my current IP address if my laptop is connected to the Internet...if not, a "server not found" answer will come.
But if an IP address (a.b.c.d) is returned, what happens next is different:
- if the user is outside the LAN (on the WAN side of the router), the web page (port 80 service) request is passed through the router to my laptop running the server. My server then responds with the home (index) page. This behavior is wanted.
- if the user is inside the LAN, with a NAT-based address assigned for private addressing systems (like 192.168.y.z or 172.16.y.z or 169.254.y.z), the router, which operates its own http server and handles port 80 service requests by delivering its configuration interface web page so that its administrator can configure the router, will instead deliver that interface web page. This behavior is NOT wanted.
The LAN side is configured using the private address system: 192.168.0.x, with subnet mask configured for all address numbers x. Let's say mine is 192.168.0.2, so the router is configured not to firewall any port 80 request and to pass all requests to the host with 192.168.0.2. It does this with no problem for those on the WAN side (outside the LAN). But for users inside the LAN, it delivers the router's own configuration interface web page, not what is wanted.
Now someone might say, "well, this is logical, because if the router needs to make its configuration interface available from the LAN side to its administrator, and if it is told not to handle port 80 requests from the LAN side, then the administrator cannot ever gain access to the configuration interface."
Actually that's not so. The router can instead be instructed (configured) to use another port number for any service request coming from the LAN side. For example, most http (web) servers are configured not only to handle requests from port 80, but also port 8080 (outside the standard first 1024 port numbers). The administrator can use this port or even change the port number for gaining access to the configuration interface.
But I am guessing that routers are just not set up for that...or perhaps the cheap models most use are not set up for that.
Right now, LAN users must type in "http://192.168.0.2" to their client to get the web page when they are inside the LAN, instead of being able to use the name. But having to tell the users to use two different links, depending upon whether they are outside or inside the LAN is just not the way it should be.