How DNS lookup works here
DNS maps a name to addresses, mail hosts and text policies. After a change, resolvers may keep the old answer until TTL expires — that lag is DNS propagation. Google 8.8.8.8, Cloudflare 1.1.1.1 and Quad9 9.9.9.9 can disagree for a short time.
IPTOOL fetches A, AAAA, CNAME, MX, NS, SOA, TXT, CAA, SRV, DS and DNSKEY. The report also checks parent nameservers, glue, SOA serial, MX and the www A/AAAA records. SPF, DKIM and DMARC have their own tools.
Shortcut: open iptool.tr/yourdomain.com. No account. You see what this Linux host got from the internet, not your home resolver cache. Whois, ping, SSL and IP geolocation use the same free terms.
.tr names go to TRABİS whois; .com and .net to Verisign. Check certificate expiry on the SSL checker and the egress IP on the DNSBL scan. Nothing here asks you to sign up.
DNS records and the zone report
A maps the site to IPv4, AAAA to IPv6. MX is inbound mail, NS which nameservers hold the zone, SOA the serial, TXT SPF and other text. CAA limits which CAs may issue. ALL queries those types together; pick one type to narrow. Parent NS and www checks live on the full DNS report.
Email authentication: SPF, DKIM, DMARC
SPF lists who may send as you in a TXT record; the include chain must stay at or under 10 DNS lookups. DKIM signs outbound mail; the selector sits at selector._domainkey. DMARC applies none, quarantine or reject when SPF and DKIM do not align. No MX means the name cannot receive mail. Ports 25, 465 and 587 are probed on the mail-server test.
IP, ping and path
What is my IP shows your address, GeoIP city/country, ISP and ASN on a map. That pin is not GPS. Ping measures ICMP latency from this host; traceroute lists hops. The CIDR calculator shows /24 and /64 ranges; the port check one allowed TCP port. RFC1918 addresses are refused.
TLS, HTTP headers and blacklists
The SSL checker handshakes on 443: SAN, days left, chain and TLS 1.2/1.3. Let’s Encrypt is usually 90 days. HSTS, CSP, X-Frame-Options and nosniff harden the browser; gaps affect the letter grade. If the sending IP is on Spamhaus, SpamCop or Barracuda, delivery drops; delist via each list’s own form.
Linux: hash, inodes, VPS size
Use SHA-256 for integrity and bcrypt for passwords; MD5 is weak. On ext4, running out of inodes stops writes while bytes remain — watch with df -i. The VPS ruler gives a rough CPU/RAM/disk range for web, mail or databases; real need comes from measurement.