Tools

• NMAP : a free open-source network scanner 
  https://nmap.org
  
  
• Advanced IP Scanner : free network scanner to analyse LAN. 
  https://www.advanced-ip-scanner.com
  
  
• Awebanalysis : IP directory for IPv4 and IPv6. Network, Trace and SEO online tools, Web Analysis and IP address location and WHOIS
  https://awebanalysis.com/en/
  
  
• MXToolBox : _{DNS Lookup, Email Blacklists, Email Header Analyzer SPF Record Check Network Tools}
  https://mxtoolbox.com/
  
  
• Evernote: Note taking, organizing, task management, and archiving
  https://evernote.com/
  
  
• Devolutions Remote Desktop Manager (RDM) Free Edition : Centralizes remote connections on a single platform 
  https://remotedesktopmanager.com/home/downloadfree
  
  
• PuTTY – Free and open-source terminal emulator, serial console and network file transfer application. It supports several network protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection.
  https://www.putty.org
  
  
• WinSCP – Free and open-source SFTP, FTP, WebDAV, Amazon S3 and SCP client for Microsoft Windows and Its main function: secure file transfer between a local and a remote computer.
  https://winscp.net/eng/download.php
  
  
• Days Calculator: Days Between Two Dates
  https://www.timeanddate.com/date/duration.html?d1=01&m1=01&y1=1970&d2=&m2=&y2=&ti=on&
  
  
• Blocklist
  https://blocklist.cyberthreatcoalition.org/vetted/
  
  

• Anti-Malware Test files
  https://www.eicar.org/

• know what browser you’re using,
  https://www.whatismybrowser.com/

• Free online service performs a deep analysis of the configuration of any SSL web server on the public Internet
  https://www.ssllabs.com/ssltest/
  
  

  Test the encryption of webservers / mailservers

• https://ssl-tools.net/

Cert Organizations 

• US CERT 
  https://www.us-cert.gov/
• EU CERT
  https://www.cert.europa.eu
• Cvedetails 
  https://www.cvedetails.com/index.php
• Israel  National Cyber Directorate (Hebrew)
  https://www.gov.il/he/departments/israel_national_cyber_directorate

Linux / Unix Tutorials  
Linux and Unix tutorials for new and seasoned sysadmin

• https://www.cyberciti.biz/faq
  
  SPF -All about Sender Policy Framework 
• http://www.open-spf.org/