SuperTool
All of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool. Input a domain name or IP Address or Host Name. Links in the results will guide you to other relevent tools and information. And you'll have a chronological history of your results
http://www.mxtoolbox.com/SuperTool.aspx
MX Lookup
his test will list MX records for a domain in priority order. The MX lookup is done directly against the domain's authoritative name server, so changes to MX Records should show up instantly. You can click Diagnostics , which will connect to the mail server, verify reverse DNS records, perform a simple Open Relay check and measure response time performance. You may also check each MX record (IP Address) against 147 DNS based blacklists . (Commonly called RBLs, DNSBLs)
http://www.mxtoolbox.com
SMTP Diagnostics
This test will connect to a mail server via SMTP, perform a simple Open Relay Test and verify the server has a reverse DNS (PTR) record. It will also measure the response times for the mail server. If you don't know your mail server's address, start with a MX Lookup.
http://www.mxtoolbox.com/diagnostic.aspx
Blacklists
This test will check a mail server IP address against 147 DNS based email blacklists. (Commonly called Realtime blacklist, DNSBL or RBL). If your mail server has been blacklisted, some email you send may not be delivered. Email blacklists are a common way of reducing spam.
http://www.mxtoolbox.com/blacklists.aspx
