We have Good Experience Using GMail for Roundtrip Monitoring

Email round trip sensors ensure the end-to-end delivery of emails and make it possible to monitor availability and performance of a complete email delivery process.

In order to test your own mail servers for delivery to external mail accounts, you need a third party mail account on the Internet. Our experience is that round trip monitoring works very well with Google Mail, as it operates reliably and there are virtually no downtimes on Google's side (which means practically no false alarms).

A Sample Scenario for an EMail Roundtrip Sensor using Gmail

• PRTG delivers an email for a dedicated Googlemail account into our mail server (MS Exchange)
• The exchange server delivers the email to Googlemail
• The email account is set to auto-forwarding to a dedicated email address on our email domain
• Extra: Googlemail delivers the email to your AntiSpam service to make sure the mail is not regarded Spam on your side
• Finally the email is delivered to our exchange server via SMTP
• PRTG scans the dedicated mailbox using IMAP (or POP3) until the email arrives

Background: What a Round Trip Sensor can Monitor

This test is great because it checks so many aspects:

• Does my mail server accept emails that need to be relayed to the outside world?
• Does my mail server actually deliver emails to the outside world?
• Are MX records for my email domain set correctly?
• Can email be delivered to my mail server?
• Can my mail server receive emails?
• Does my mail server process and forward incoming mails correctly?
• Can users access their emails using POP/IMAP?
• Does all this happen in a timely manner?
• Are all necessary Internet connections working?

If any of these aspects was broken, an email round trip sensor would fail.

Our Monitoring Results

Here is a report for Dec2009–Mar2010 for our round trip monitoring: