Infrastructure and Hosting Terms
The setup behind your website and email decides how easy your business is to impersonate, how fast you come back after a failure, and how exposed your servers are. These terms cover email authentication, DNS, certificates, backups, and hosting in plain English. Each one links to the RFCs and agency guidance that define it.
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- DDoS attack: An attempt to knock a service offline by flooding it with traffic or requests from many machines at once.
- TLS certificate: A digital credential that proves a server belongs to its domain and enables encrypted HTTPS connections.
- DNS hijacking: An attack that changes a domain's DNS records so its website or email points to attacker-controlled servers.
- DNSSEC: Security extensions that digitally sign DNS records so resolvers can verify answers are authentic and unaltered.
- SPF: An email authentication standard that lets a domain publish in DNS which mail servers are allowed to send email on its behalf.
- DKIM: An email authentication standard that adds a cryptographic signature to messages, verified with a public key published in the sending domain's DNS.
- DMARC: A DNS policy record that tells receiving mail servers how to handle email that fails SPF or DKIM alignment for your domain, and where to send reports.
- Backups and the 3-2-1 rule: A backup practice of keeping three copies of important data on two types of storage with one copy off-site, so one event cannot destroy every copy.
- Recovery point objective (RPO): The maximum amount of data, measured in time, that a business can afford to lose in an outage, set by how recent the last usable copy is.
- Recovery time objective (RTO): The maximum time a system or service can stay down after a disruption before the impact on the business becomes unacceptable.
- PHP end of life: The date after which the PHP project stops releasing security fixes for a PHP version.
Last updated October 14, 2026.