Online-Tools:

• gitignore.io
• CyberChef
• Modern Internet Standards provide for more reliability and further growth of the Internet. Are you using them?
• prettifyjs.net
• Pingdom Website Speed Test
• Awesome Asset Discovery
• North Data
• Webseiten vergleichen mit PrivacyScore
• webbkoll
• socialbearing Twitter Analyse
• We send it Dateien bis 5 GB versenden (automatisch ver- und entschlüsselt)
• Magic-Wormhole: Get Things From One Computer To Another, Safely
• DNS Dumpster
• urlscan.io

Online WHOIS & andere

• many tools
• Network Tools
• central ops

Twitter

• The one million tweet map
• OmniSci Tweetmap

weitere Tools:

• Advanced IP Scanner
• MobaXterm Enhanced terminal for Windows with X11 server, tabbed SSH client, network tools and much more

Toolsammlungen

• Open Source Intelligence Tools für Journalisten
• Open Source Security Tools List
• OSINT Tools - Investigating websites

Nachschlagen:

• Elektronik Kompendium IT-Grundlagen
• Privacy-Handbuch
• Ross Anderson - Security Engineering — Third Edition
• Router-FAQ

E-Mail Infos, Checks, etc.

• E-Mail Header Analyzer (gaijin.at)
• Email Header Analyzer (MX Toolbox)
• E-Mail-Header lesen und verstehen
• E-Mail Header finden und verstehen
• SPF Record sender policy framework
• 1secMail temporäre E-Mail-Adresse

Video/ Tutorials

• Sebastian Philippi/sephi IT-Grundlagen
• Andreas Thehos Excel
• Christian Spannagel Math for the Masses