Watch a packet travel from host to server. Open full screen ↗  recommended on mobile (rotate to landscape) How to read it Each tower is a device, and each square is a layer of the TCP/IP stack (4 layers, not OSI's 7): Physical, Link, Internet, and Transport — applications live above the stack (the dashed boxes) and use …

Interactive course Authentication and Secrets — how a request proves who sent it, from a password in a header to a workload that never holds one: Basic auth and sessions, keys and signatures, TLS and certificate chains, mTLS, JWT, OAuth2 and OIDC with Keycloak, and secrets with Vault and AWS. Worked in your own …

For a random IPv4 address + mask (e.g. 178.178.178.178/24), answer three things: Class — is the address Class A, B, or C? Scope — is the mask the class's default, a subnet (longer than default), or a supernet (shorter than default — aggregating multiple classful networks, e.g. 193.15.4.7/16 is one address in a block …

What is DNS Informally, we could say that DNS (Domain Name System) allows users to use names instead of IP addresses. The initial thinking was that names are easier to remember and work with, so users will find it easier to use them. In fact, DNS is part of the network itself. For example, you could run a single …

NAT - What problem are we going to solve There are several types of NAT (Network Address Translation) We are going to address here the most complex one, because it is what you would usually encounter in your home/caffee etc. Other types of NAT are usefull as well (we'll cover those in other posts). For example, in AWS …