Troubleshooting Email SystemTools… it’s hard to fix anything without tools. Every sys admin knows that they have to have a collection of tools, and more importantly, the right tools for the right job. While many of the best tools are ones that we install when we need them, or even add to our base image so that they are already on a machine when required, sometimes we need more.

There are two big benefits to online tools. The first is that, as long as you have Internet access, they are always there and ready for you. The second, and this is the big one for email systems, is that they exist outside the system you are troubleshooting. That means they have the same point-of-view as other external systems, and far too often it’s the interactions with other systems that we have to troubleshoot. We’ve scoured the web to compile this list of 42 great online resources for troubleshooting your email system. Each of these tools is online and ready to go. If you have a browser and Internet access, you’ve got what you need to use these tools.

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.

1.Exchange ActiveSync

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)’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? 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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