Mailserver Absenderbeschränkung

Last modified by Aysegül Omus on 2024/03/04 14:15

Change of mail server settings due to mail server sender restrictions

1. Mail server sender restrictions

If you send emails via the ITO or TUM mail server address and use sender addresses from other providers, the emails will be blocked and not sent.

Many mail providers (e.g. T-Online, GMail, ...) no longer accept it and classify such e-mails as spam if emails are sent from servers different from the one that the sender address specifies. It is important that the mail server matches the mail address for each identity.

If you would like to continue sending emails via our outgoing mail server, you should change the sender address to your address. The settings for this are described on our Wiki

If you want to continue using a different sender, you must change the outgoing mail server. This is described below for the case that you want to use a address as the sender. If you want to use an external provider such as Gmail as the sender, you must find out the outgoing mail server from the external provider's documentation, after which you can set it up as described in this guide.

2. Editing the outgoing mail server for the TUM identity in Thunderbird

If you have the e-mail address e.g. in an identity and have set as the outgoing e-mail server, the e-mails will be blocked by many e-mail providers. If you use the email address in the identity, then must be set as the outgoing mail server so that the emails can be sent.

With the help of the following screenshots we will show you how to add the outgoing mail server to the TUM identity.

2.1. Add outgoing mail server (SMTP) for the identity of the TUM e-mail address

Before you can change the outgoing mail server, you must first add it in Thunderbird.

First click on Thunderbird -> Preferences in the top menu.


Then click on Account Settings.


In the opened window click Outgoing Server (SMTP). All outgoing mail servers are listed here.


Click on Add and enter on Server Name and your LRZ ID as User Name. Then click on OK.



2.2. Select LRZ outgoing mail server (SMTP) for TUM identity

First click on your email address and then on Manage identities


Select the identity of the TUM email address and click Edit.


Select the LRZ outgoing mail server from the drop-down menu and click on OK.



You can also set up the TUM account in your mail program and use your TUM certificate without an identity. You can find more information about setting up the TUM account here.

Note: If multiple accounts are configured in Thunderbird, multiple identities can be configured for each account. Therefore check all settings until you find the problem area.

If you have any further questions, please feel free to email us at