[BUG] SMTP Validation may fail from Ruby 3.0 onwards

[esb]

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[BUG] Ruby 3.0 changes the handling of SSL certificate verification which will cause failures when the certificate names don't match the IP addresses.

Bug description

The interface for the Net::SMTP start method changed in 3.0 to

start(address, port = nil, helo: 'localhost', user: nil, secret: nil, authtype: nil, tls_verify: true, tls_hostname: nil) { |smtp| ... }

The old method continues to be supported, but it looks like they changed to enable tls_verify by default. Under the 2.7 library, there's no problem connecting to gmail.com, but from 3.0 you get a connection error stating that there's a certificate error.

My feeling is that SSL errors are irrelevant for email verification, so tls_verify should always be off, and a quick way to fix this is to add the tls_verify: false option to the SMTP start method, although you would need to check the library version and only do this for versions 3.0+.

[bestwebua]

Hello, @esb! Thanks for your bug report. I have tested this behaviour on Ruby 3.0.0 and I confirm this bug:

I'm going to fix this issue till the end of this week.

[bestwebua]

@esb, this fix is available in latest (2.5.3) truemail release. Cheers!