Edit Copy page Copy page as Markdown for LLMs Open in ChatGPT Ask ChatGPT about this page Open in Claude Ask Claude about this page Fundamentals of the Internet Edit Copy page Copy page as Markdown for LLMs Open in ChatGPT Ask ChatGPT about this page Open in Claude Ask Claude about this page DNS IP Address, Ports, Components of a domain A/CNAME/MX records ISPs Routers Previous Page Introduction Next Page Introduction Last updated 3 months ago