Domains and DNS
The DNS Lookup shows A, AAAA, MX, TXT, NS and CAA records from public resolvers, which is the first check after pointing a domain to new hosting. The WHOIS Lookup shows the registrar, expiry date, transfer lock and nameservers, and What Is My IP shows your public address and network for firewall rules and allowlists.
HTTPS and the padlock
When a browser says Not Secure, the cause is usually an expired or mismatched certificate, a missing intermediate certificate, or mixed content. The SSL Certificate Checker tests trust, expiry, the chain, TLS version and HSTS, and the Mixed Content Checker finds every http:// file that breaks the padlock. Our guide to why a site says Not Secure walks through each fix.
Email deliverability and safe sharing
Google and Yahoo now require bulk senders to authenticate email. The SPF and DMARC Checker reads and grades your records and flags the common mistakes, explained further in SPF, DKIM and DMARC explained. To send a password or login to a client, create an encrypted, self-destructing Secret Share link instead of putting it in an email.
Frequently asked questions
How long do DNS changes take?
Most changes show up within minutes to a few hours. The old value can linger until its TTL (time to live) expires, which is often set to an hour or a day, so lower the TTL before a planned move.
Why does my site say Not Secure even with an SSL certificate?
The usual causes are an expired certificate, a certificate for a different name (such as www versus the bare domain), a missing intermediate certificate, or images and scripts still loading over http://.
What is the safest way to send a password to a client?
Use a one-time, encrypted link that deletes itself after it's opened, and send any passphrase through a different channel such as a text message, so the password never sits in an email thread.