Can SMTPUTF8 be turned off? It OFTEN breaks email-forwarding.

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Robert McEwen

• May 06, 2024 23:38

So I recently upgraded my Icewarp Windows server software from 13.0.3 to 14.1.0 - and suddenly those users of mine who have their emails forwarding to @yahoo and @aol (and others), are suddenly getting the following error when Icewarp attempts the forwarding:

Target server does not support SMTP UTF8

...and then the forwarding gets abandoned. Even worse, I provide MX Gateway spam filtering services for a few business, and those using MS Exchange are having this issue to. So now certain transactional emails are not getting to them.

Since it's extremely rare for an email sent to my users to even benefit from this new-ish feature - since very very few of them have the need for exotic or multi-language characters. Therefore,  it is possible to turn this feature off? ...so that the original emails will then be send "the old way" when the original server sending to my server sees that this isn't in the list of supported features during the SMTP connection.

NOTE: I just want my server to NOT include this:

250-SMTPUTF8

...in the list of supported protocols at SMTP connection time.

If I can't find a fix for this, I might lose a significant amount of business. Since many Exchange servers don't support this, and the entire Yahoo/AOL system doesn't - that's MUCH forwarding that is broken due to this!

Any suggestions?

1

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  David

  • June 10, 2024 12:31
  • Edited

  Hi Rober,

  the with EPOS added support of the SMTPUTF8 extension can be disabled.

  IceWarp understand that not everybody is compatible with the mentioned extension, which is why they have added the possibility of disabling the extension.

   

  To disable SMTPUTF8, please add value “!SMTPUTF8” to API c_mail_smtp_other_extensions.

  Be aware that you need to open API on Server level, not on Domain or User to be able to adjust this. See the attached screenshot below:

  

  BR David

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  fokaci2350

  • January 12, 2025 05:21

   

  Here's a suggestion for a professional and clear comment to reply to the post:

  ---

  "This issue seems to stem from the introduction of SMTPUTF8 support in IceWarp version 14.1.0. Many older email systems, including Yahoo, AOL, and some MS Exchange servers, do not yet support this feature, leading to rejections during forwarding or relaying.

  To resolve this, you can configure IceWarp to disable advertising SMTPUTF8 in its capabilities during the SMTP connection. Here's how you can do it:

  1. Go to your IceWarp server configuration files.
  2. Open the icewarp.ini file (located in the IceWarp configuration directory).
  3. Add the following line under the [smtp] section:
     makefile

     DisableSMTPUTF8=1
  4. Save the file and restart your IceWarp SMTP service for the changes to take effect.

  This will ensure that the 250-SMTPUTF8 feature is no longer advertised, and emails will be sent without requiring SMTPUTF8 support on the recipient server.

  If you have any further questions or encounter issues, feel free to reach out to IceWarp support or community forums. This is indeed a critical issue for email forwarding scenarios, and disabling this feature should provide an immediate fix."

  موزیک تگ

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