Subnet Calculator: https://community.spiceworks.com/tools/subnet-calc/
SMTP IP Blacklist check: https://mxtoolbox.com/SuperTool.aspx
MD5 Checker: https://www.winmd5.com/
TFTP Server: https://www.solarwinds.com/free-tools/free-tftp-server
Tera Term : https://osdn.net/projects/ttssh2/releases/
Notification texts go here... Link
Reach out!