MxToolBox - All of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool.
NinjaOne - NinjaOne (Formerly NinjaRMM) provides remote monitoring and management software that combines powerful functionality with a fast, modern UI. Easily remediate IT issues, automate common tasks, and support end-users with powerful IT management tools.
Dnsstuff - DNSstuff offers DNS tools, Network tools, Email tools, DNS reporting and IP information gathering.
Microsoft Operations Management Suite - Microsoft Operations Management Suite enables user to gain visibility and control across the hybrid cloud with simplified operations management and security
SPF Toolbox - SPFtoolbox is a Javascript and PHP app to look up DNS records such as SPF, MX, Whois, and more
Atera - Atera’s all-in-one platform enables IT professionals to gain access, visibility, and control over all their networks and devices from anywhere, so they can work smarter and light years faster.