online network tools

• IP Address
• Subnet Calculator
• https://www.blockstatus.com
• http://www.urlsuite.com/
• http://www.urltrends.com
  

mailing lists and newsletters

• http://www.phplist.com
• http://www.gnu.org/software/mailman/index.html
• http://www.dioscouri.com
  

network storage solution

• https://www.getdropbox.com/