We are sending emails through a Microsoft connector, which verifies the sending server's IP address and sender email address. We started getting these error messages recently:

Symfony\Component\Messenger\Exception\HandlerFailedException(code: 450):Handling "\Symfony\\Component\\Mailer\\Messenger\\SendEmailMessage" failed:Expected response code "250" but got code "450", with message"450 4.7.26 Service does not accept messages sent over IPv6"

Apparently, our server started to connect using IPv6 and the connector only accepts IPv4 addresses. With this PR, we can force the SocketStream to connect to the smtp server via IPv4, by supplying an option in the DSN. Example usage:

MAILER_DSN=smtp://<mydomain>.mail.protection.outlook.com:25?force_ipv4=true

This is my first PR to Symfony, so I tried doing my best to follow the guide.

From the errors I received, I think with DKIM signing IPv6 should be allowed as well. However, I do not have access the DNS records and needed a quick fix. This PR is based on a patch I did in my own project. Probably I will implement an available Microsoft Graph Transport in the future. But perhaps it's worth to keep this option available as well.

carsonbot added Status: Needs Review Feature Mailer labels

Jan 11, 2025

carsonbot added this to the7.3 milestone

Jan 11, 2025

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carsonbot commentedJan 11, 2025

Hey!

I see that this is your first PR. That is great! Welcome!

Symfony has acontribution guide which I suggest you to read.

In short:

Always add tests
Keep backward compatibility (seehttps://symfony.com/bc).
Bug fixes must be submitted against the lowest maintained branch where they apply (seehttps://symfony.com/releases)
Features and deprecations must be submitted against the 7.3 branch.

Review the GitHub status checks of your pull request and try to solve the reported issues. If some tests are failing, try to see if they are failing because of this change.

When two Symfony core team members approve this change, it will be merged and you will become an official Symfony contributor!
If this PR is merged in a lower version branch, it will be merged up to all maintained branches within a few days.

I am going to sit back now and wait for the reviews.

Cheers!

Carsonbot

nicolas-grekas reviewed

Jan 13, 2025

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nicolas-grekas reviewed

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quilius force-pushed thefeature/bindToIpv4 branch from100d478 toa848d95Compare

January 14, 2025 21:57

fabpot reviewed

Jan 15, 2025

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stof reviewed

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		@@ -6,6 +6,7 @@ CHANGELOG

		* Add DSN param `retry_period` to override default email transport retry period
		* Add `Dsn::getBooleanOption()`
		* Add DSN param `source_ip` to allow binding to a specific IPv4 or IPv6 address. If you want to bind IPv4 without specifying an address, use `0.0.0.0`.