Email, Spam Control, Attachment filters

On this page, you can learn the types of files that are not allowed as email attachments to or from addresses


As part of its efforts to protect the University of Illinois from malware and other email threats, Technology Services at Illinois blocks certain types of files from being sent or received as email attachments.

Tech Services does not expect that this or any one single solution will solve all problems associated with email security. But filtering these file types, combined with other steps, should help reduce the spread of phishing emails and malware on campus.

Q: How can I tell if an attachment has been filtered?

  1. If you receive an email that has a filtered attachment, a text file attachment will be added to the message stating that an attachment was filtered.
  2. If you send an email with an attachment that gets filtered, the recipient of the email will see additional text file attachment to your message stating that an attachment was filtered.

Q: I need to send or receive a file that is being filtered. What can I do?

The best way to send files is not through email attachments, but through Cloud-based supported file sharing services.

Q: Which file types are being filtered?

Previously, Tech Services Spam Control focused on blocking attachments that it had scanned and determined were malware. Now, in addition to scanning for and deleting malware sent by email, particular file types sent as email attachments will be removed from the emails
  • These file types are frequently used to try and deliver malware to campus through email. 
Tech Services does not expect these blocks to directly impact most email users as common formats of documents, spreadsheets, PDFs, and graphic files will not be filtered. 
  • However, if these files have embedded macros then they will be removed.
  • Please note that archive file types (.zip, .rar, .tar, etc.) will only be automatically filtered if they ARE encrypted or password protected. This is because if the archive uses a password or encryptions, we cannot tell if the archive contains malware. 
  • If the file is not encrypted, it will still be scanned for malware and blocked only if malware is detected.

 Archive files that are NOT password protected, NOT encrypted, and do NOT contain malware, can be sent and received normally.  

These executable file types are removed from email sent or received by email accounts.


































































































































These archive files types are allowed as long as they can be scanned. 

  • If the archive is encrypted, password protected or contains malware, then the file will be removed from the email.













KeywordsEmail spam control strip strips filter remove attachment file type prohibit prohibited block .exe blocked attachment   Doc ID51416
OwnerEmail Relays E.GroupUniversity of Illinois Technology Services
Created2015-05-14 13:40:13Updated2020-12-19 14:17:39
SitesUniversity of Illinois Technology Services
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