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All Articles - Page 2
25 total articles
What to Fix Before Requesting IP Blacklist Delisting
If a mail server IP is blacklisted, do not request delisting before you fix the root cause. This guide covers reverse DNS, domain authentication, compromise checks, and the cleanup steps that should happen first.
How to Check PTR Before Sending Email From a VPS
Before sending email from a VPS, verify the PTR record on the server IP. This guide explains how reverse DNS works, why it matters for deliverability, and what to fix if the record is missing or inconsistent.
Mail Goes to Spam Even With SPF and DKIM
SPF and DKIM passing is a good start, but it does not guarantee inbox placement. This guide explains what to check next, including DMARC, reverse DNS, blacklist status, content signals, and sending reputation.
IP WHOIS Lookup, How to Identify Who Owns an IP, Find the ASN, and Investigate Abuse Fast
This guide shows how to use IP WHOIS to identify who owns an IP address, understand ASN and carrier context, validate geolocation as a signal, and turn the output into practical actions, abuse reporting, blocking decisions, and correlation with reverse DNS and blacklist status.
IP Blacklist Checker, How to Diagnose Email Deliverability Issues and Delist Safely
This tutorial shows how to diagnose email deliverability problems by checking your outbound sending IP against major DNSBL and RBL blacklists, how to interpret different listing types, and how to fix the real root causes, compromised accounts, relay issues, missing PTR and authentication
How to Remove Empty Lines Cleanly, Without Breaking Paragraphs or Lists
This article shows how to remove empty lines from text safely, including whitespace-only lines, and how to preserve readable formatting by collapsing multiple blank lines into one. It includes real examples for lists, paragraphs, and logs, plus troubleshooting tips.
How to Randomize a List Fairly, Pick Winners, and Reproduce Results (Seeded Shuffle)
This tutorial shows how to randomize lists fairly using an unbiased shuffle, how to keep header lines fixed, how to pick N winners without repeats, and how to use a seed to reproduce the same randomized result for audits and transparency.
How to Find Your Real Origin IP Behind Cloudflare, Safely (and How to Fix Leaks)
Cloudflare hides your origin IP only for traffic that goes through Cloudflare’s proxy. That usually means your A and CNAME records for the website are “proxied” (orange cloud). But some DNS records cannot be proxied, and email is the biggest one.
CSS Minifier and Beautifier: When to Minify, When to Beautify, and How to Avoid Breaking Your Layout
This guide explains how to minify CSS for faster delivery, beautify CSS for debugging, and remove comments safely without breaking behavior. It includes practical WordPress workflow advice, common failure cases like broken braces and unterminated comments, and a verification checklist after deploy
SSL Certificate Chain Errors: What They Mean, and How to Fix Them (With a Live Checker)
This article breaks down the most common SSL certificate chain errors, what each error actually means, and the exact fixes that resolve them, including deploying fullchain files, correcting intermediate certificates, fixing hostname mismatches
Why IPv6 Ping Fails, 10 Real Causes and Fixes (With Live Tests)
This guide explains why IPv6 ping often fails even when a website is online, then walks through 10 real-world causes like missing AAAA records, broken IPv6 routing, ISP path issues, and ICMPv6 firewall blocks. It shows how to test correctly using a live IPv6 ping tool, how to tell DNS problems from
SPF, DKIM, DMARC Explained (With Live Checks), plus Fixes That Actually Work
SPF tells receivers which servers are allowed to send mail for your domain. DKIM adds a cryptographic signature to outgoing emails, receivers verify it using your public key in DNS. DMARC tells receivers what to do if SPF and or DKIM fail, and it enforces alignment with the visible From domain.
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