The Microsoft® Remote Connectivity Analyzer
This is the probably the single largest collection of tools online all in one place, though obviously its focus is on Exchange, both on-premise and online. The RCA includes a total of 11 tools specifically designed to test Exchange on-premise systems, though five of those can easily be used to test other email systems. While the RCA also has tools for Lync and Office 365, here’s a rundown of the 11 that are usable on-premise. The last five can be used to test any email system even if it is not Exchange.
2. Exchange ActiveSync Autodiscover
3. Synchronization, Notification, Availability, and Automatic Replies
4. Service Account Access (Developers)
5. Outlook Anywhere (RPC over HTTP)
6. Outlook Autodiscover
7. Inbound SMTP Email
8. Outbound SMTP Email
9. POP Email
10. IMAP Email
11. Message Analyzer
Network Abuse Clearinghouse Mail relay testing
Here’s an online test that can help you to confirm whether or not your new email server is misconfigured and susceptible to abuse as an open relay. It offers both anonymous and registered user testing. Anonymous is not as thorough nor as accurate, but gives you an idea whether or not something is wrong, as the inaccuracies result in false positives, not negatives. Registered users can test by actually attempting to relay mail and receive results in their inbox.
12. Mail relay testing (anonymous)
13. Mail relay testing (registered user)
MailTester.com’s Email address verification
This tool can take a provided email address and provide both an MX record lookup on the domain, and a VRFY test against the MX servers to see if the email address is valid. Of course, that presumes that servers respond to VRFY (many won’t) but it is a quick way to get MTA names and ip.addrs.
14. Email address verification
Microsoft’s Sender ID Framework SPF Record Wizard
Here’s a wizard that can be used to create valid and correctly formatted Sender Policy Framework (SPF) records. It will perform MX and A record lookups for a given domain, ask you some simple questions that include options for outsourced services and RFC compliant records, and then will generate a valid SPF record that you can paste into your DNS zone file.
15. SPF Record Wizard
Kitterman’s SPF Record Testing Tools
Once you have an SPF record, you can use this site to validate that it is formatted correctly and entered into your DNS as a proper TXT record. It also offers SPF retrieval and testing using another MTA.
16. SPF Record lookup
17. SPF Record syntax validation
18. SPF Record testing
WebSitePulse’s Email Validation Test
Another online test to validate based on a specific email address, this tool can test from multiple locations and validate all the servers listed in your MX records.
19. Email Address Validation Test
MxToolbox Online SMTP Diagnostic Tools
SMTP Diagnostics will connect to your email server, test for open relay, verify the DNS PTR record, and measure response times.
20. SMTP Diagnostics
MxToolbox Email Header Analyzer
MxToolbox also has an SMTP header analyzer tool. Paste in the header from an email message, and see each hop in the path including server, delay, and more.
21. Email Header Analyzer
DNSstuff Email Tools
Click on the Email Tools tab in this site, and you will see a vast array of tests that can used to validate practically any aspect of your email system that could be of interest from the outside.
22. DKIM Key Checker
23. Check for valid SPF record
24. External email sending test
25. Spam Blacklist Lookup
26. Email Path Analyzer
27. SMTP Banner
28. SMTP Greeting
29. Null Sender permitted
30. Postmaster accepted
31. SMTP Abuse check
32. Accept email sent to ip.addr(not server name)
33. Open Relay check
34. POP Banner
35. POP Authorization
36. POP Status
37. IMAP Banner
38. IMAP Authorization
39. IMAP Status
Kloth’s Multi DNSBL-check
Have you ever wondered if your email system is on a blacklist? Kloth.net can query eighteen of the most popular DNSBLs for you in one tool.
40. DNS Blacklist lookup
Central Ops free online network tools
Central Ops includes several good networking tools on this page. The one we’re interested in for email is the Email Dossier check. Given an email address it will do validation results, MX record check, and attempt an SMTP session with the email server.
41. Email Dossier
Rolosoft email address checker
Another tool that can perform a verification that an email address exists on a remote system, assuming the remote system supports VRFY.
42. Email address checker
When we started this list, our goal was to provide a list of the best online tools available to an email SysAdmin. We did not set out to create a list with X number of tools, or have any preconceived notion of how many tools were out there. That we came up with 42 without trying to get to that number is just another in the long list of cosmic signs out there that clearly show 42 is the answer! Whether you bookmark and use all 42, or just pick a couple, we hope this list has turned you onto some online resources you didn’t know about that are out there to help you troubleshoot your email systems.
If you have a favorite that we left off or you have your own site that offers some great tools for sys admins, leave a comment and let us know. We’re always interested in learning about new sites and your comment will help us and other readers!
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