UDE Mailpolicy

Quota on Mailbox-Servers

The maximum mailbox size on the ZIM’s Mailbox-Servers is limited. Mails that exceed this limit will be rejected. You can find further information here.

E-Mail Adresses for Alumni

After leaving UDE, all your clearances and resources will be removed via a defined process. You can set up a redirection to any external mail address. However, there will be no university mailbox connected to your UDE address anymore! You can find further information here.

Protection from Viruses, Malware etc.

To provide a reliable protection from viruses, malware and ads for our employees and students, the ZIM uses special servers.

These servers check all incoming mail traffic in a special filter process before accepting them and putting them in the queue. (=> Pre-Queue-Filter).

Benefit: Legal Safety

From a legal standpoint, we are not allowed to suppress or delete an accepted e-mail. This means, that if our server accepts an e-mail with malware, we still would have to deliver said e-mail to the user. (§206 StGB, Violation of Postal Secrecy and Secrecy of Telecommunications)

Technical Details

You can find details to our defense measures under Spam Defense from November 2016.

Mail Traffic Limitations

Maximum Number of Recipients

You can send one e-mail (sum of To:, CC: and BCC:) to a maximum of 99 recipients.

Maximum E-Mail Size on All Systems

100.000.000 bytes (~100MB)

The actual size of an attachment can however be smaller.

Maximum E-Mail Size on the Webmail-Interface:

6.000.000 bytes (~6MB) when using an IMAP webmail program.

-> to send larger attachments, you can use the Gigamove service.

Spam-Protection Settings

Every member of the UDE can view their current settings in the Selfcare-Portal (under “Mail-Funktionalitäten” -> “SPAM Schutzmaßnahmen einstellen”) and if needed choose a new individual spam-defense strategy.

In communication with data security and the staff councils, these standard settings for spam-defense are in place for all users:

  • As a standard we have the “medium” protection setting. With this, a mail, classified as spam, will not be accepted.
  • We categorically reject mails with viruses or executable attachments to ensure business security. The recipient will not get notified about the rejected mail. The sender however will (as described under Pre-Queue-Filtering) get notified.


As an additional feature, our users now have the option to use “greylisting”. Greylisting is a form of spam-defense, where the first e-mail of unknown senders get rejected at first and will only be accepted after another delivery attempt.

You can find further information on these settings under “Options in the Selfcare-Portal for E-Mail Procedures”.

Treatment of Recognized Viruses, Spam etc.

Viruses, Malware, Executable Attachments

When processing electronic messages, the new systems carry out further checks for viruses, spam and executable attachments. Should these checks come out with a positive result, the mail will not be delivered. The potential recipient of the infected e-mail will be notified about the discarded mail. This is how notifications about viruses, malware or executable attachments look like.  


Attachments in Old Microsoft-Formats

File attachments in old office formats (like .xls, .doc and .ppt) are often used to spread e-mail malware. That is why, since 07-01-2019, the UDE does not accept e-mails with such attachments anymore. You can find additional information on that here.

Please do not use these old formats altogether and change your files to newer formats (like .xlsx, .docx and .pptx).


Should the new systems classify the contents of a message as spam, an additional X-header line “X-Spam-Sore:” will be inserted. Depending on the degree of spam probability, the system will give the mail either 5 (“low” spam probability) or 10 (“high” spam probability) stars.

Protection Against Spam From the Inside

The ZIM cannot always prevent, that a user’s login data gets into the wrong hands. These “hacked” IDs have been abused in the past to send unwanted advertising e-mails (“Spam”) in masses to various recipients outside of the university.

The worst case is that the university’s mail servers will not accept any e-mails anymore. 

To minimize the effects of spam distribution via the webmailer, using a hacked ID, the user guidelines for the webmail services have been tightened (see Protection Against SPAM)