Troubleshooting Email Issues

Zip file attachments

The background

• Zip files are a very common way to spread ransomware and other nasty payloads that can compromise your data
• For this reason, zip files are a blocked attachment type, the server will not accept them by default
  • The server also blocks other kinds of file types that can be run as programs, such as .exe and .bat files

The Solution

• Computerisms can disable the block on zip attachments
  • Disabling the block affects the whole domain, so we cannot prevent individual users @yourdomain.com from receiving zip files without blocking them for everybody.
    • This puts the onus on the end-users to not open zip files that they do not recognize.
    • Because of the dangers of ransomware crippling your entire network, we do not recommend opening any zip file attachment without first contacting the sender and confirming it is a legitimate file
• The Sender can rename the attachment from file.zip to file.zi_ before sending
  • Most of the time, this will fool the server into letting the mail through
  • When the mail is received, the recipient will have to save the file, and then rename it from file.zi_ back to file.zip