Tag email security

DMARC – One protocol to bind them all

DMARC tells the receiving email server what do when SPF and DKIM policy checks fail. However DMARC performs another vital step. DMARC checks that that the domain of the author, as seen by the end-user fully the domain validated by…

DKIM – Why you need it

DKIM (DomainKeys Identified Mail) is an email authentication mechanism that lets a sending domain sign an email. Think of DKIM as a tamper-evident seal on an email envelope. If someone opens it and messes with the contents, the seal is broken, and the fraud…

Redirect domains explained

Redirected domains are web domains that don’t directly host services. Instead they act as aliases, and redirect users to your authoritative (a.k.a. canonical) site. Redirected domains have some security weaknesses, but we’ll get to that later. First we’ll examine the…

Protect your reputation with SPF

You’ve just receive an email from a client saying: “Thanks — we’ve paid the invoice to the new bank account as instructed.” Super. No. Wait. What? You never sent them an email. Fuck! What happened? This type of attack is known…