Terms

Web

Load Balancers - give high traffic websites the ability to handle large amounts of traffic and provide a failover if a server becomes unresponsive.
- Can use different algorithms such as round-robin (sends requests to each server in turn) or weighted (checks how many requests a server is currently dealing with).
- Load Balancers will perform health checks to ensure a server is running correctly.
CDN (Content Delivery Networks) - allows for the hosting of static files to a website across numerous servers and sends requests to whatever server is closest to the requestor.
WAF (Web Application Firewall) - sits between web request and web server; will stop common attack techniques and can drop potential requests.

Web servers listen for incoming connections. Common ones being:

Nginx and Apache (Linux-based) - serve files from /var/www/html/.
IIS (Windows-based) - serve files from C:\inetpub\wwwroot\.
Virtual Hosts - allows web servers to host multiple websites by checking the hostname being requested from the HTTP header and matches it against a virtual host (e.g. /var/www/website_one, /var/www/website_two, etc.).
Static Content - content that never changes (e.g. pictures, js, css, etc.).
Dynamic Conent - content that can change with requests (e.g. blogs).