Security & email
SSL/TLS certificates, DNSSEC and the SPF, DKIM and DMARC records that protect your domain and email from interception and spoofing.
4 guides
How SSL/TLS Certificates Work and Why They Fail
A plain-language explanation of TLS certificates: the handshake, certificate chains and authorities, how hostnames are matched, automated renewal with ACME, and the most common certificate errors and their causes.
What DMARC Does: Alignment, Policies and Reports
DMARC ties SPF and DKIM to the From address people actually see, tells receivers what to do with mail that fails, and sends you reports. Learn how alignment, policies and reporting work, and how to roll it out safely.
What Is DNSSEC? Signatures, Keys and the Chain of Trust
DNSSEC adds cryptographic signatures to DNS so resolvers can detect forged or altered answers. Learn how keys, DS records and the chain of trust work, what validation failures look like, and the most common way domains break.
What SPF Does: Syntax, Qualifiers and the Lookup Limit
SPF lets a domain list the servers allowed to send its email. Learn how SPF records are written, what -all and ~all mean, why you can only have one record, how the 10-lookup limit works and what SPF cannot protect.