Synchresis Toolbox.

Free diagnostics for the things that drive IT people mad.

What gets checked

A traffic-light report across every layer that has to work for your site to load and your mail to be trusted — modelled on the classic comprehensive DNS report, brought up to date with modern email-security standards.

Domain

  • Domain registration & expiryRegistrar, lock status and how long until the domain expires.

DNS

  • Parent delegation & glueHow the TLD points the world at your nameservers.
  • NameserversAre your nameservers plural, diverse, healthy and in agreement?
  • SOA recordThe zone’s "start of authority" timers and serial.
  • DNSSECIs your DNS cryptographically signed and validating?

Web

  • Website addresses (A / AAAA)The IPv4 / IPv6 addresses your domain points to.
  • Website reachabilityDoes the site load over HTTP and redirect to HTTPS?
  • Website TLS certificateIs the HTTPS certificate valid, trusted and current?
  • CAA recordsWhich certificate authorities may issue certs for you.

Mail

  • Mail routing (MX)Where inbound email for the domain is delivered.
  • Mail server connectivityDo your mail servers answer, greet and offer encryption?
  • SPF – sender authorizationWhich servers are allowed to send mail as your domain.
  • DKIM – signing keysPublished public keys that prove your mail is genuine.
  • DMARC – policy & reportingYour published policy for handling forged mail.
  • Mail transport securityMTA-STS, TLS-RPT and DANE for encrypted mail delivery.

Reputation

  • IP blacklists (DNSBL)Are your web / mail IPs on common block lists?