Good day

I have setup redirect on DNS and SMTP for my clients so that they use the ISPs settings without having to go to each and every client. all is working except for those that have SMTP servers that require authentication. It fails unless that button is unchecked. Is there a way for the mikrotik to handle this setting?

Regards

router has no control over SMTP traffic and options that are advertised by SMTP server. All you can do is to configure your SMPT server to accept clients even if they are proving logging credentials that are not correct.

On the other hand it would be better to inform users that outgoing SMTP is only available through ISP SMTP server or they should use encryption (SSL/TLS) to communicate with SMTP server of their preference.

oh well. it works for those who dont have 'my server requires authentication.' at least we wont be visiting every customer.

the smtp server is unfortunately controlled by the isp and they only allow us to use their server.

Thanks anyway

What about Layer7? And search if user is sending AUTH data, and re-redirect them to their servers?

you can filter those packets, you cannot change settings that are sent. Also there is a problem, redirect has to be done when connection is initialized, and options are sent afterwards, so you have a problem - connection is established and you cannot redirect that any more.