How can I force Exim to check the validity of an email before sending it?

Question

Debian

How can I force Exim to check the validity of an email before sending it?
That is, if the email is not valid, then do not send a letter there, do not even try to send it there (for example, write an invalid email to the log)

Answer 1

The validity of the email is already checked before sending (acl with the verify = recipient directive). The truth for remote hosts - only the domain. You can check by sending a request via SMTP to check if the recipient exists by changing the acl to: verify = recipient/callout=10s. This action will cause additional load on the server.
If you really need to add regex validation, I guess you'll have to use built-in perl and some script like this www.commandlinefu.com/commands/view/10321/validate...