Internet
Internet
This domain covers how networks and the web work: network types, addressing, DNS, URLs, protocols and browser behaviour. CCC+ asks for the function of a protocol or the part of a URL, not deep configuration.
Core rules
- A network links devices. LAN is local; WAN covers a wide area; the Internet is a global network of networks. An ISP provides access.
- An IP address identifies a device/interface; IPv4 is 32-bit (four decimal octets), IPv6 is 128-bit hexadecimal. A MAC address is a hardware address used on a local link. DNS translates domain names such as example.com into IP addresses.
- HTTP/HTTPS transfer web pages; HTTPS adds TLS encryption and normally uses port 443. FTP transfers files between hosts.
- A URL has a scheme, host, optional port, path and query. Browsers cache resources and use cookies to store state.
Worked example
In https://www.example.com:443/exam/page?q=1, https is the scheme, www.example.com the host, 443 the port, /exam/page the path, and q=1 the query. Reasoning: the scheme appears before ://; the host follows; the path starts after the first slash following the authority. Because HTTPS defaults to 443, the port may be omitted.
Traps
The Internet is not the same as the WWW: the web is one service on the Internet. An IP address is not a MAC address. Incognito mode does not hide traffic from an ISP or make you anonymous. HTTP is not encrypted; HTTPS is. A domain name is not a URL.