Can I use a non-existent source email address for zabbix?

It is up to the SMTP server specified in Zabbix to accept test transmissions using non-existent email addresses.

Typically, production SMTP servers check the existence of source email addresses as follows:

• Mail from inside (local network)
  Is the domain managed by the source email address?
  Does the user with the source email address exist?
• Email from outside (Internet)
  Is there a server that can receive mail from the source mail address domain?(MX and A records available and possibly connected to the server)

However, they are not always configured and may only be checked partially or not at all.In other words, some SMTP servers accept e-mail addresses that do not exist.Therefore, if you specify such an SMTP server, you can set it up on Zabbix itself.Postfixes on the same server can work only because mail from the local host is set not to check the source email address.In other words, if there is no other SMTP server to accept without checking the source, you have to create such an SMTP server or put Postfix on the same server.

Now, be aware that "configurable" and "actually sent" are different.The only thing Zabbix can tell from Zabbix's mail sending test is that the mail was sent to the SMTP server.If the SMTP server is not the final destination of the destination, we do not know if it was sent to the destination mailbox.If you use a non-existent email address as the source, it may not be sent.If the source mail address domain does not exist, you may refuse to receive mail.In this case, the rejected mail will try to return an error mail to the sender, but the source email address does not exist in the first place, so it will not be sent anywhere (error mail will be sent to MAILER-DAEMON, but only the server administrator can check it).

It might work even if the address is completely ridiculous.However, if you use an e-mail address that does not exist, be aware that there is always a possibility that the e-mail will not be sent correctly.If you want to send mail without any problems, we recommend that you use an email address that you can receive properly.