Definition

The DNS (domain name system) is the system that translates human-readable domain names (e.g. ipzen.com) into IP addresses that machines can use. It is the global directory of the internet, without which web browsing as we know it would be impossible.

What it does in practice

• Routes web traffic to the right server
• Manages email records (MX) for deliverability
• Verifies sender identity through SPF, DKIM and DMARC
• Configures subdomains (app., blog., shop.)

Security stakes

DNS is also a prime attack target: cache poisoning, DNS hijacking, takeover of records. Consequences can be severe: email interception, redirection to fraudulent sites, indirect cybersquatting.

Best practices

• Choose a reliable, redundant DNS provider
• Activate DNSSEC to cryptographically sign records
• Monitor DNS modifications
• Centralise domain name management in a single tool to avoid missed renewals