We greatly appreciate the feedback from our Free Monitoring Tool users regarding the issue of Server Alerts not being delivered. We are currently working on it and it should be fixed shortly.
This is just one of the features included in the Free Monitoring Tool and we encourage our customers to continue using the product. Please continue to let us know your feedback or any improvements you would like to see.
Stay tuned to our blog and Forums for more updates.
UPDATE 5/20/2009 @ 8:59pm: Server Alerts are now functioning again, we apologize to everyone for this interruption in service. We were working on upgrade the database and code and the most recent code roll out did cause a problem. We have resolved this problem at this time.
UPDATE 5/22/2009: We are aware that the Free Monitoring Tool is issuing some false positive alerts at this time. We are working on correcting this as quickly as possible.
UPDATE 5/22/2009: The false positive problem has been brought under control. There were two issues, both related to a software update. The first was that previously, we were only alerting if your email server failed to accept our TCP connection on port 25. Sending us a 400 SMTP error would not generate an alert. The code change caused servers that were either issuing 40x errors OR terminating our SMTP connections abruptly to be flagged as down. The numerous UP/down alerts were caused by servers that were running anti-spam software and intermittently refusing our SMTP sessions or issuing 400 deferrals.
Remember, to reduce the chance of false positives from our monitoring service, you should whitelist 18.104.22.168/24 on your email servers or gateways that we are monitoring.
We have restored the behavior of ONLY alerting you that your server is down if it fails to accept a TCP connection on port 25. Second, we have increased our timeouts, giving slow or busy servers more time to respond before flagging them as down.
We appreciate your patience as we have worked to resolve this and sincerely regret any trouble this has caused you.