Articles & Guides
Useful resources for web developers and system administrators
AI
How to Promote a Website in AI Neural Networks (GEO)
Promote your website in AI answers (ChatGPT, Perplexity, Google AI Overviews, Gemini): the three GEO pillars, cited content formats, llms.txt, and a checklist.
AI
Google AI Overviews: How to Rank and Turn It Off
How to rank in Google AI Overviews: query fan-out, E-E-A-T, extractable passages, Schema. Impact on CTR and traffic, plus how to turn AI Overviews off.
AI
Yandex Neuro: How to Appear in Its AI Answers
How Yandex Neuro works, which signals its neuro-search uses to pick sources, and what raises your citation odds. Factors, checklist and a free test.
Networking
SMTP Errors 550 and 554: Causes and Fixes
SMTP errors 550 and 554 explained: what the codes mean, enhanced 5.x.x status codes, rejection causes (SPF, DKIM, DMARC, blacklist) and how to fix them fast.
DNS
SOA DNS Record: Fields, Serial, and How to Read It
Understand the SOA DNS record: all fields (MNAME, RNAME, serial, refresh, retry, expire, minimum), the YYYYMMDDnn serial format, zone transfers, and dig checks.
DNS
SRV DNS Record: Syntax, Priority, Examples
What an SRV DNS record is per RFC 2782: the _service._proto.name syntax, how priority and weight work, examples for SIP and XMPP, and common mistakes.
DNS
TXT DNS Record: What It's For and How to Add It
What a TXT DNS record is and why you need it (verification, SPF, DKIM, DMARC, BIMI), the 255-character limit, quoting syntax, and how to add and verify it.
DNS
NS DNS Record: What It Is and How to Check It
What an NS DNS record is and how zone delegation works: primary and secondary servers, glue records, checking NS with dig and WHOIS, changing NS servers and common mistakes.
Networking
What Is MTU: Fragmentation and How to Fix Issues
What MTU and MSS are, typical values (1500, 1492, jumbo 9000), Path MTU Discovery and black holes. How to measure MTU with ping and set it on your OS.
Networking
SMTP Port 25 vs 465 vs 587: Which to Use and How to Test It
Port 25 relays mail between servers; 587 (STARTTLS) and 465 (implicit TLS) are for clients. Gmail settings, TCP vs UDP, common errors and test commands.