ToolWeb Link
DNS Toolshttps://tools.cliftonsystems.co.uk
Password Generatorhttps://passwordsgenerator.net/
Raid Calculatorhttp://www.raid-calculator.com/
DNS Propergationhttps://dnschecker.org
Email Header Analysishttps://mxtoolbox.com/EmailHeaders.aspx
Blacklist Checkerhttps://mxtoolbox.com/blacklists.aspx
SPF Checkerhttps://www.kitterman.com/spf/validate.html
https://www.spfwizard.net/
Ping, Tracroute and Pathping
Speedtesthttps://fast.com/
Check Secure Emailhttps://www.checktls.com/index.html/spf/validate.html