What is port 80?

Port 80 is the default port that web server use and the default port that your web browser use to connect to web servers, how do web browser work, what if port 80 is closed and well known web server.

Port 80 is the default port that web server use, when you open your browser to surf the web and you type in the url you want to visit it try to connect the site through port 80 as this is the default port for HTTP traffic, as you know web site start with the protocol, like http or https, even if you don’t type it the web browser add it automatic for you.

So here is a brief intro about what happened after you type a url in your web browser:

  • The URL is translate to an ip address, using the DNS service, it will ask your DNS if it know this domain name (aka:url) and if not it will check with more DNS services, if it will not get an answer you will gate the error 404 Page Not Found.
  • After in found the server IP address it will try to connect it on port 80 if it manage it will request, GET, the site content, it will download the page to your local temporary internet folder, if you open this folder you can actually find the files in there.
  • Web browser only support HTML, Javascript, CSS aka Client Side code, the server is loading the PHP or ASP, ASPX code and generate an HTML page that is sending to your web browser for display.
  • Your web browser will parse the data it receives and build the page according to the HTML tags that it find, javascript, include ajax etc will be part of the page view and enrich the the site and CSS will design the page, where to put what (images, boxes etc).

To open port 80 on your server, after installing a web server, in case that it is not reachable from outside your local lan can be due to a firewall that configure to block port 80, you can also check if you have a router that it configure to forward request into port 80, this can be archived by configuring your firewall and your router.

Some well-known web server include:

  1. Apache – Open source web server that is widely use, probably the one that used by most Linux servers and the one that is most used in the world.
  2. Tomcat – Used a lot for web service, also part of Apache.
  3. IIS – Web server from Microsoft.
  4. Weblogic – was from BEA Systems, now it own by Oracle.

In conclusion port 80 is the default port that use by web servers, each time that you request a web page in your web browser it send a request to the web site server using port 80, parse the data according to the page that you request and send it back to your web browser for view.

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