# Star Computers

> Field notes on cloud architecture, infrastructure, and systems engineering — plus practical tools for cloud and network operators.

Site: https://starcomputers.in
RSS: https://starcomputers.in/rss.xml
Full text index: https://starcomputers.in/llms-full.txt

## Topics covered
- AWS
- Google Cloud
- Azure
- Cloud
- Kubernetes
- Containers
- Terraform
- Ansible
- DevOps
- CI/CD
- Networking
- DNS
- Security
- IAM
- Observability
- Monitoring
- Linux
- Databases
- Cost Optimization
- Architecture
- AI
- LLMs
- Generative AI
- India

## Articles
- [Cloud, systems, and the plumbing in between](https://starcomputers.in/blog/cloud-systems-plumbing) — 2026-04-20
  Most infrastructure outages happen at the seams — between clouds, networks, and tools. A walkthrough of where reliability is won or lost: hybrid connectivity, Linux and containers, networking, IaC, observability, day-2 ops, automation, and small internal tools.
- [How India is using AI in 2026: from awareness to daily application](https://starcomputers.in/blog/how-india-is-using-ai-in-2026) — 2026-04-19
  Search intent in India has shifted from "what is ChatGPT" to practical, task-oriented queries — using AI at work, in school, for small businesses, in regional languages. Posts that answer these questions with concrete steps, honest limits, and structured FAQs are what Google AI Overviews and Perplexity cite.
- [Welcome to the new Star Computers](https://starcomputers.in/blog/welcome-to-star-computers) — 2026-04-19
  The site is now an Astro-powered static blog with markdown posts, typed tags, JSON-LD structured data, RSS, and an llms.txt for answer engines. Writing posts now means editing one markdown file and pushing.
- [A pragmatic approach to AWS IAM policies](https://starcomputers.in/blog/a-pragmatic-approach-to-aws-iam-policies) — 2026-04-12
  Model access by workload not by person, prefer conditions over bespoke policies, always attach a permissions boundary to roles you issue to other teams, and review policies on a cadence.
- [The DNS 'propagation' myth and what actually happens](https://starcomputers.in/blog/dns-propagation-myth) — 2026-04-05
  There's no propagation — only TTLs expiring in resolver caches worldwide. Pre-lowering your TTL before a change is the only real speed-up.

## Tools
- [BIMI Lookup](https://starcomputers.in/tools/bimi-lookup) — Find and parse a domain's BIMI record. Shows the logo URL, Verified Mark Certificate, and previews the SVG as mail clients will render it.
- [Blacklist (RBL / DNSBL) Check](https://starcomputers.in/tools/blacklist-check) — Check an IP address or domain against 15+ reputable DNS-based blacklists in parallel. Identifies listings that may affect mail deliverability.
- [CAA Record Lookup](https://starcomputers.in/tools/caa-lookup) — Find and interpret CAA (Certification Authority Authorization) records. Walks the DNS tree to show which CA is allowed to issue certs for a domain.
- [Certificate Transparency Search](https://starcomputers.in/tools/certificate-transparency) — Find every TLS certificate ever issued for a domain. Query the public CT logs via crt.sh to discover forgotten subdomains and unauthorized issuance.
- [CIDR / Subnet Calculator](https://starcomputers.in/tools/cidr-calculator) — Expand an IPv4 CIDR block into its network address, broadcast, netmask, wildcard, usable host range, and total address count.
- [DKIM Lookup](https://starcomputers.in/tools/dkim-lookup) — Fetch a DKIM public key from DNS by selector and domain. Detects revoked keys and parses tags like version, key type, and flags.
- [DMARC Lookup](https://starcomputers.in/tools/dmarc-lookup) — Fetch and parse the DMARC policy for a domain. Explains each tag and flags common weaknesses like monitor-only mode, missing reports, or sub-100 pct.
- [DNS Lookup](https://starcomputers.in/tools/dns-lookup) — Inspect A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, PTR, and SRV records for any domain, with response codes and TTLs, from your browser.
- [DNSSEC Check](https://starcomputers.in/tools/dnssec-check) — Check whether a domain is DNSSEC-signed. Shows DS and DNSKEY records, algorithm and digest type, and whether the resolver returned an authenticated (AD) response.
- [Email Header Analyzer](https://starcomputers.in/tools/email-headers) — Paste raw email headers to trace the delivery path, check SPF/DKIM/DMARC authentication, and spot delays between MTAs.
- [Email breach checker](https://starcomputers.in/tools/email-leak) — Check whether an email address appears in known public breaches. Uses XposedOrNot breach data; the email is never logged by this site.
- [Hash Generator](https://starcomputers.in/tools/hash-generator) — Compute SHA-1, SHA-256, SHA-384, and SHA-512 of any text. Runs entirely in the browser via the Web Crypto API — your input never leaves the device.
- [HTTP Header Check](https://starcomputers.in/tools/http-headers) — Fetch a URL and display the response headers, status, redirects, and timing. Highlights missing common security headers (HSTS, CSP, X-Frame-Options, etc.).
- [IP Address Info](https://starcomputers.in/tools/ip-info) — GeoIP, ASN, ISP, reverse DNS, and allocation info for any IPv4 or IPv6 address. Leave blank to look up your own IP.
- [JWT Decoder](https://starcomputers.in/tools/jwt-decoder) — Decode the header and payload of a JSON Web Token. Shows claims, expiration status, and kid/alg — all in the browser. Signatures are not verified.
- [MTA-STS Lookup](https://starcomputers.in/tools/mta-sts-lookup) — Check whether a domain publishes MTA-STS — the policy that forces TLS on incoming SMTP and prevents opportunistic-TLS downgrade attacks.
- [MX Lookup](https://starcomputers.in/tools/mx-lookup) — Find the mail exchangers for a domain, sorted by preference, with TTL. Useful for verifying MX records after a DNS change or diagnosing mail delivery issues.
- [Reverse DNS (PTR) Lookup](https://starcomputers.in/tools/reverse-dns) — Resolve an IPv4 or IPv6 address back to its PTR record. Useful for mail deliverability and sanity-checking what a remote IP claims to be.
- [SPF Lookup](https://starcomputers.in/tools/spf-lookup) — Find and parse the SPF (Sender Policy Framework) record for a domain. Explains each mechanism and flags common misconfigurations like +all or over-10 DNS lookups.
- [Timestamp Converter](https://starcomputers.in/tools/timestamp-converter) — Convert between Unix epoch (seconds and milliseconds), ISO 8601, RFC 2822, and your local timezone. Accepts "now" and relative formats.
- [TLS-RPT Lookup](https://starcomputers.in/tools/tls-rpt-lookup) — Check the SMTP TLS Reporting record (RFC 8460) for a domain. Verifies where TLS failure reports from sending MTAs are delivered.
- [Username scanner (WhatsMyName)](https://starcomputers.in/tools/whatsmyname) — Check where a username is registered across ~35 social, coding, gaming, and media sites. Useful for OSINT, brand-name recon, and privacy audits.
- [WHOIS / RDAP Lookup](https://starcomputers.in/tools/whois-lookup) — Registrar info, registration dates, nameservers, and status for a domain, plus allocation and ASN data for an IP. Uses RDAP — the modern JSON-based replacement for WHOIS.