How are pages fetched -- address resolution for internal website and IIS.

Posted on 2013-11-22
Last Modified: 2013-11-22
I am new to web programming.

I am learning IIS.

Within a company firewall, there is website, that is, I suspect, is not available to the rest of the world outside the firewall.
(I made this link up to look similar to my company link, where is in place of my company name).

How is the address resolved?
What is the process?

Is there a dedicated server that points all internal addresses, such as
to a particular machine and particular port?  (If so, what is the name of the program or tool that keeps track of all these mappings).

IIS seems to let you create new websites that use the same port as other websites on the machine--it doesn't force you to create a new port for each website.

So how does it know which website to pick?
Question by:kamistry
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LVL 58

Accepted Solution

Gary earned 500 total points
ID: 39670133
All browsers operate on port 80 (443 for SSL) unless you specifically set a different port.
When you put a site address into the browser then the browser will first check its host file to see if there is already an IP entry for the address and if not sends this to the local DNS server.
The DNS server to use will be configured on each PC.  The most common one for the home user would be Google's DNS - IP address
The DNS server will translate the address to an IP address of the server hosting the domain and tell your browser this is where it needs to look.
Your pc then connects to the server with that IP and sends the domain address.
The server receiving a connection on port 80/443 will know to send this request to whichever HTTP server is running (IIS/Apache etc will listen on these ports for any communications) which in turn will look at its own configuration to determine where that domains files resides and returns them to the browser

That's the not so technical version.

Author Comment

ID: 39670272
Where does the host file live on my windows 7 PC?

You're saying each PC is configured to use a certain DNS server.
Where is that setting on my windows 7 PC?
(I am not a home user -- company network)

Does the net result of the DNS translation amount to an IP Address + Port?
Correct me if I am wrong, but hypothetically speaking, DNS might translate the following link:

(Can I type this into the broswer as-is?  If not, what is the right syntax to bypass the DNS)
LVL 58

Assisted Solution

Gary earned 500 total points
ID: 39670315
On Windows the hosts file is located in
C:\Windows\System32\drivers\etc\ - or the derivative version of the folders depending the OS

The DNS will depend on your ISP/Sys Admin. In Control Panel/Network and Sharing Center click Change Adapter Settings and right click what would likely be name Local Area Connection and select properties.
Select Internet Protocal Version 4 and click Properties - this will show the DNS settings, it may be Automatic

If you type in

The DNS server will return

The browsers connects to the IP (on 443) and sends this to it.

The DNS server is only there to tell your browser the IP to use - it knows nothing of ports.

If you type in the server will return the default domain.  Since a server may have multiple domains it needs the actual domain name to know what site you are looking for.
If you only use the IP then the default domain will be used (if any domain is setup as the default)
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Author Comment

ID: 39670362
if  DNS  only returns the IP and not the port, then how is it that, by typing: 
(I didn't define any port in the link)

into your browser,

the right site is returned?

There can be multiple web sites on the server.
How does it pick the site?

Are you saying that one of my sites is the default site?

How do I know which one is my default site?
LVL 58

Assisted Solution

Gary earned 500 total points
ID: 39670372
http uses port 80
https tells it to use 443

It picks the site based on the domain name -

If you only use the IP and your site comes up then it is one of two things - there is only that single site hosted on the server or it is the default domain.

Author Comment

ID: 39670414
Now it makes sense!
You are awesome.

Author Comment

ID: 39670467
I've requested that this question be closed as follows:

Accepted answer: 167 points for GaryC123's comment #a39670372
Assisted answer: 167 points for GaryC123's comment #a39670133
Assisted answer: 0 points for kamistry's comment #a39670272
Assisted answer: 166 points for GaryC123's comment #a39670315
Assisted answer: 0 points for kamistry's comment #a39670362

for the following reason:

The interaction lead to the solution.
LVL 58

Expert Comment

ID: 39670430
When closing a question and awarding points you don't select your own comments as part of the answers.

Author Comment

ID: 39670468
I'm new to this.
Does that count against the person in some way (like point split or something like that)?
If so, I will try and see if I can adjust that.
But if not, then the reason was that it was a dialog and I wanted folks to see the interaction.
LVL 58

Expert Comment

ID: 39670479
No but there is no point selecting a comment where you are asking a question as one of the answers - and it just delays the closing process.
I will amend the Accepted Answer to my comments

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