MX Toolbox

MX Toolbox is a web-based application that will check domain names and return DNS info, Time To Live (TTL) for DNS records, who the email provider is for a domain, and where the IP address of the email server is located. For example, Amsterdam for a Northern European Office 365 hosted email domain. MX Toolbox can also do a Blacklist Check against 90+ blacklist providers to see if your email domain IP address has been blacklisted as a SPAM relay, or for any other reason. MX Toolbox is available here.