![]() If it doesn't already know the IP of, or that information is too old, it will ask whatever the DNS server for the IP of "". Computers use IP addresses to talk, so if you provide them names, they need to convert them first. Your computer uses DNS to convert a name like into an IP address. I've even simplified DNS above - the DNS protocol includes things like distributing data, controlling how long that data is good for, determining the final point of authority, and so on.Īccording to my knowledge about IP address and DNS server, when I type in the address bar on Chrome and then press the Enter button, with DNS server (E.g: Google DNS server), my browser will redirect to 8.8.8.8 IP address if there is no cache stored in my computer, right? ![]() Keep in mind, there's a lot of other stuff happening behind the scenes on your computer and other computers on the internet when you use a web browser: DNS, routing, load balancing, port forwarding, etc. Google's DNS servers aren't listening to HTTP/HTTPS requests, just DNS requests. If you do try to "direct dial" by supplying the IP address in your web browser, the server on the other end has to be expecting a web browser request for a web page (listening to the proper ports for HTTP or HTTPS, configured with a response, etc). Your computer then uses that IP (without showing it to you) in place of the URL. Your computer asks the DNS server what IP that name corresponds to, and the DNS server returns the IP. In the case of web browsing, the lookup process happens behind the scenes. You wouldn't expect that to successfully dial, would you? You use the book to look up the right number, then dial that number on the phone - it's a multi-step process. Pointing your web browser directly at 8.8.8.8 is like smacking the telephone book with the phone handset. You can access 8.8.8.8, but it only responds to the right questions.Ī DNS server is akin to a telephone book. However, they still need to have IP addresses in order to transfer anything through the internet at all.) (Finally, a system could have an IP address and not offer any service at all – like your computer or phone, which mostly just act as clients and access services hosted elsewhere. Your browser specifically asks to connect to the server at port 443 the server recognizes it as a protocol that it doesn't provide and rejects the connection entirely before the browser could even begin to send the real request. Generally, all such protocols have different "port numbers" assigned to them – HTTPS has 443, DNS has 53, and so on. Websites are accessed using the HTTP protocol, but you could find many examples of services that run over the internet, but don't use the web nor HTTP (after all, the internet had been in use for a good decade before the web was invented) – DNS is one such service, email is another, and most online games aren't actually web-based either. Or in other words, the internet's job is to transfer data around between IP addresses, and a website is just one specific kind of data (in a similar way that news broadcasts are just one of many things that can be shown on TV). ![]() "Web" isn't exactly the same thing as "internet" – it is just one of many different services that happen to be carried over the internet. Close the command prompt to complete this activity.8.8.8.8 is a public IP address, if it's not a webpage, what would it be?.The first TTL count which results in success indicates the number of routers or "hops" between your computer and Google's public DNS server. Then repeat the ping command, each time increasing the TTL (-i) parameter by one until the ping is successful again. Type ping -i 2 8.8.8.8 and press Enter.The response should also indicate the IP address of the router where the TTL expired. The ping request should fail with TTL expired in transit. Type ping -i 1 8.8.8.8 and press Enter.8.8.8.8 is the IPv4 address of one of Google's public DNS servers. These activities will show you how to use the ping command with a custom TTL.Īctivity 1 - Ping with a Custom TTL The ping command has an option to configure the Time To Live (TTL) of the packet to be transmitted.
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