I have got apache up and running on my Linux machine. My friend can see my web pages using the external IP Address.

ALso I can see my own web pages using my internal IP address eg 192.168.1.2, BUT i cannot see it using the external address.

Even on another computer on my local network I cannot see it.

It is not the firewall as I have it turned off.

Any suggestions welcome

Regards
Shelton.

What kind of local network do you have setup? Is it running through a router with NAT enabled? I am assuming you won't be able to access it with that IP since it is out of the network range for your subnet.

Yes it is running though my ADSL modem which is a router with NAT applied. My subnet mask is 255.255.255.0

Regards
Shelton.

This makes sense then. The external IP will not be available because your PC won't know how to route the data since it whole conception of the network is in the 192.168.0.x range. Is their a particular reason why you need to use the other IP?

Hi Unreal

I wanted to see my webpages from the external address - I mean if it does not work as you explaned -then I understand.

Thnks for replies.

Regards,
Shelton.

Then how is it possible to see other external web sites Unreal - like www.google.com ?

Regards
Shelton.

Ok, so you know what DNS is right? every computer has an IP and every network has a bunch of IPs? And you understand that routing details how to get network to and from computers in networks?

The reason why you can't see the page internally is because you don't have a route to it, your network and the internet don't have information on how to get to the external address of your web site. The reason you can see google is because DNS servers from your ISP and routers of your ISP have information on how to translate www.google.com into the IP of google, route the traffic, and bring the page back.

What you DO have in your internal network, is a route to the web page on the internal IP. What your friend has, is a route and/or a DNS entry to the external IP.
So in short, two things determine if you can see a web page. A router contains the route to the page, and a DNS server has a name<->number translation. You are missing one or the other in any case where you can't see the page.

Hope this explains what is going on here;

When you send the request it goes from your box on the lan to the router which then sends the request out using the wan ip address allocated by the isp. Since the ip address of the request and the response are the same the system gets confused and says that it cannot be found.
This can be overcome using network loopback (I don't know how to do this so don't ask) or by finding a public proxy server or using a different ip address to make the request. A public proxy server is one which redirects requests form one ip and makes it look like it is coming its coming from the proxy server thereby allowing the request. I have used this method and it works well. Make sure that the proxy server allows you to do this! You can also use a dial-up connection because this will come from a different ip.

Edit: You'll find a list of proxy servers here . Use the anonymous ones on port 80. To do this with Mozilla/FireFox go to Edit -> Preferences -> Connection - Manual proxy configuration and enter the address and use port 80.

ok thanks for the explantion Tiger!

The easiest way is to edit /etc/hosts file,

insert something like

192.168.1.x www.yourdomain.com www

where 192.168.1.x would be your internal IP address of your web server, can be any class A,B or C and www.yourdomain.com would be the FQDN. So whenever you type www.yourdomain.com or www into your browser url, it resolves to the 192.168.1.x where your web server would be

My router (Linksys WRT54G) adds a loopback route for the public IP address and does not suffer from this problem. Any machine on my LAN can browse the public-facing web server using my router's public IP address or dyndns.org hostname.

hi sti2envy
yes that fixed the problem - it was the host file that I needed to make an enty!

Thanks again!

Regards
Shelton.

i had a linksys router at my old house that did the same thing. i've since used both a microsoft wireless router and a different linksys cable modem/gateway/router, and neither of them allows that by default. i asked why, and was told that it's a design decision: that computers inside a LAN should only communicate with the server inside the LAN. routing traffic through the gateway to the external interface and then back in to the server creates extra complexity and sucks up extra system resources.

while this is probably more applicable to large networks, i think it's still good policy to be efficient whenever possible.