Tools

• Reverse DNS
• Reverse IP Lookup
• WHOIS Information
• Domain Location
• Hosting Checker
• Domain Search
• Key Generator
• Self-signed SSL Generator

DNS Checker

• https://www.whatsmydns.net/ - web site propogration
• How to find all subdomains of a domain
• Search for hosts/SSL

SSL Checker

• https://www.ssllabs.com/ssltest/
• https://www.sslshopper.com/ssl-checker.html

Online Malware Scanner

• https://sitecheck.sucuri.net

Site Checker

• https://geopeeker.com
• https://shotsherpa.com
• https://www.browserling.com
• https://search.google.com/test/rich-results

Google Search Console

• https://search.google.com/test/mobile-friendly

Web site Tools

• https://www.uptrends.com/tools/traceroute

Site Speed

• https://gtmetrix.com
• https://developers.google.com/speed/pagespeed/insights/
• https://tools.pingdom.com/fpt/
• https://developers.facebook.com/tools/debug/og/object/
• https://www.uptrends.com/tools/uptime

Email Checker

• mail-tester.com - Test the Spammyness of your Emails.
• https://dkimvalidator.com/ - Test SPF/DKIM/DMAC.
• MXtoolbox.com - Text your DNS MX records.
• SenderScore.org - Know your sender reputation
• https://www.checktls.com/TestReceiver

IP

• https://ip.serverok.in
• https://search.censys.io/ - Find website IP address history.

WHOIS

• Domain Dossier
• https://internic.net/whois.html - check IP of name server

Security

• shodan.io - Shodan is the world's first search engine for Internet-connected devices. Discover how Internet intelligence can help you make better decisions.

CIDR

• https://www.ultratools.com/tools/netMask - CIDR to Netmask (for hosts.allow)
• https://ip2cidr.com
• https://cidrcalculator.com/ipv4/ip-range-to-cidr/?cy=USD
• http://www.subnet-calculator.com/cidr.php - IP CIDR Calculator

DNS Checking

• http://www.dnsinspect.com
• http://www.dnsstuff.com/tools
• http://www.intodns.com
• http://dnscheck.pingdom.com
• http://ViewDNS.info

Ping

• https://www.dnsstuff.com/tools
• https://host-tracker.com/ - Check your site availability in different country

TraceRoute

• https://www.traceroute.org - Traceroute from various locations
• https://tools.pingdom.com/ping/

File System

• https://www.clonespy.com - Remove Duplicate files

Malware

• https://sitecheck.sucuri.net/scanner/ - Scan site for malware
• https://www.unmaskparasites.com
• https://www.stopbadware.org/clearinghouse/search

Domain

• https://www.domainsbot.com
• https://www.whois.sc