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Guides
Practical, no-fluff guides on DNS, email deliverability, SSL and network troubleshooting — each one links to the tools that put it into practice.
DNSSEC Explained: What It Is and Whether You Should Enable It
A plain-English explanation of DNSSEC: the problem it solves, how the chain of trust works, the trade-offs, and how to check if a domain is signed.
Email Deliverability Checklist: Why Your Email Goes to Spam (and How to Fix It)
A practical checklist for landing in the inbox instead of spam: authentication, reputation, list hygiene, content, and the checks to run on your own domain.
Open Ports Explained (and How to Check Them Safely)
What a network port is, what 'open' really means, the ports you should know, and how to safely check whether a port is reachable.
How to Fix 'Your Connection Is Not Private' and Other SSL Errors
What the 'Your connection is not private' warning really means, the common SSL/TLS error codes, and how to diagnose and fix each one.
What Is an ASN? (And How to Find Out Who Owns an IP Address)
Learn what an Autonomous System Number is, how IP addresses map to the organizations that run them, and how to find the owner of any IP.
How to Read a Traceroute (and Find Where the Slowness Is)
Understand every column of a traceroute, what high latency and timeouts really mean, and how to tell whether a problem is on your side or the network's.
DNS Record Types Explained: A, AAAA, MX, TXT, NS, CNAME and More
A plain-English guide to every common DNS record type, what each one does, when you would use it, and how to check it.
What Is My IP Address? (And How to Hide It)
What your IP address reveals, the difference between public, private, IPv4 and IPv6 addresses, and the real ways to hide or change it.
How to Check an SSL/TLS Certificate and Prevent Expiry Outages
Learn how to read an SSL/TLS certificate, check its expiry and chain, automate renewal with ACME, and set up monitoring so HTTPS never goes down.
How to Check DNS Propagation After Changing Records
Learn what DNS propagation really means, how TTL and caching cause delays, and how to check propagation across global resolvers after changing your records.
Why Your IP Is Blacklisted and How to Get Delisted
Find out why your IP landed on a DNS blocklist, how to check which lists flag it, and the step-by-step process to fix the cause and get delisted fast.
How to Set Up SPF, DKIM and DMARC for Email Authentication
Learn how to set up SPF, DKIM and DMARC records to stop email spoofing and boost deliverability. A step-by-step guide to authenticating your domain.