Here the client is expecting alice.txt which is text type.ĥ.Accept-Language: en-US => Accepted language standard.Ħ.User-Agent: Mozilla/5.0 (Windows NT 10.0 WOW64 Trident/7.0 rv:11.0) like Gecko => Client side browser type. Ģ.Request URI: /wireshark-labs/alice.txt => The client is asking for file alice.txt present under /Wireshark-labsģ.Request version: HTTP/1.1 => It’s HTTP version 1.1Ĥ.Accept: text/html, application/xhtml+xml, image/jxr, */* => Tells server about the type of file it can accept. HTTP GET:Īfter TCP 3-way handshake is done HTTP GET request is sent to the server and here are the important fields in the packet.ġ.Request Method: GET => The packet is a HTTP GET. Note: We will explain TCP exchanges in another topic discussion. Now let’s see what’s there inside HTTP GET and HTTP OK packets. TCP 3-way handshake -> HTTP OK -> TCP Data -> Now let’s see what happens in network when we put that URL and press enter in browser. In parallel we have capture the packets in Wireshark.īefore we go into HTTP we should know that HTTP uses port 80 and TCP as transport layer protocol.

Now we see the downloaded file in browser.So in this example we will download “alice.txt” (Data file present in server) from “gaia.cs.” server. Let’s try something practical to understand how HTTP works ? POST: POST method is used when it’s required to send some data to server.

We will see one practical example of this method. This is a main method used document retrival. GET: GET request asks data from web server. We will not go in details of each method instead we will get to know about the methods which are seen quite often.Such as GET, HEAD, POST, PUT, DELETE, CONNECT, OPTION and TRACE. There are some set of methods for HTTP/1.1 (This is HTTP version) And also HTTP defines rules for transmitting HTTP command to get data from server.įor example, when you enter a url in browser (Internet explorer, Chrome, Firefox, Safari etc) it actually sends an HTTP command to server.And server replies with appropiate command. So HTTP define reules what action should be taken when a browser receives HTTP command. HTTP is used by the World Wide Web (w.w.w) and it defines how messages are formatted and transmitted by browser. See below picture to find out HTTP which resides under application layer. HTTP is an application layer protocol in ISO or TCP/IP model. First is all the full form of HTTP is HyperText Transfer Protocol.

Wireshark command line tools exercise