vCenter is not sending email alerts

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It’s useful to get email notification when there is an alarm raised in vCenter Server. To configure the function. You need a valid SMTP server. And configure the SMTP server on vCenter Server. If there is a problem that vCenter Server is not sending email alerts. We need to isolate is it a vCenter Server side issue, or an SMTP server problem. Therefore how to identify problem source is important.

VMware moved vCenter Server to a customized Linux based platform since 5.5. It’s easy for administration, but limited ability in troubleshooting. You may notice that the telnet command is not available when troubleshooting the SMTP issue.

The following is how to troubleshoot such an issue on the vCenter Server virtual appliance.

Firstly, you need to ping the IP address and FQDN of the SMTP server. Make sure the basic connectivity between the vCenter Server and SMTP server is working.

Second, try to reach out to SMTP service on the vCenter Server to make sure the SMTP protocol can be established. Since the telnet command is unavailable on the vCenter Server virtual appliance. We use curl command as a workaround:

curl -v telnet://SMTP SERVER:SMTP PORT

For example:
curl -v telnet://zhengwu.org:25

You should see the keyword “Connected to zhengwu.org….” if the connection is successful. That means the basic connectivity between the vCenter Server and the SMTP server is working.
Then you can try sending an email manually on the vCenter Server shell. The following are the commands. Please note there is a . at the end of the command. It indicates the end of the mail.

MAIL FROM:sender@zhengwu.org RCPT TO:Reception@zhengwu.org DATA Subject: This is a testing mail This is testing content


If SMTP is working fine. You should see following message:
250 2.0.0 xxxxxx Message accepted for delivery
If all of these testing are passed. Then it maybe indicate it’s a SMTP server issue.
Following are some articles for your reference:
Emails are not sent from vCenter Server Appliance 6.5 or 6.7 after an Alert/Event is triggered.
Diagnosing why VMware vCenter Server is not sending email alerts