Table of Contents
Overview
To help protect our customers and maintain a reliable email service, we restrict certain file types from being sent or received through our email platform.
These restrictions are designed to reduce the risk of malware, ransomware, phishing attacks, and other malicious activity that commonly uses file attachments as a delivery method.
Most everyday business documents, including PDF files and standard office documents, continue to be accepted and delivered normally, until they are deemed a threat.
Why Are Certain File Types Restricted?
Cybercriminals frequently use file attachments to distribute malware and other malicious software. In many cases, dangerous files are deliberately packaged in ways that attempt to bypass security controls.
By restricting high-risk file types, we significantly reduce the likelihood of harmful content reaching customer mailboxes.
Security Risks Associated with Restricted Files
Many restricted file types can contain executable code, scripts, installers, compressed archives, or other content that may be used to hide malware.
Attackers often rely on these file types because they can conceal harmful content from users who may not realise what they are opening.
Restricting these file types provides an additional layer of protection alongside spam filtering, antivirus scanning, and other security measures.
Protecting Platform Performance
Email servers perform extensive security checks on attachments, including antivirus scanning and content analysis.
Malicious users often attempt to send large volumes of compressed or high-risk files, sometimes in bulk, to overwhelm security systems or distribute malware.
Each attachment must be processed and inspected, which consumes CPU, memory, storage, and antivirus scanning resources.
By restricting certain file types at the platform level, we help ensure that system resources remain available for legitimate customer email traffic and that mail delivery remains fast and reliable.
What File Types Can Still Be Sent?
Most common business file formats continue to be accepted with minimal issue.
- PDF documents
- Microsoft Office documents
- Spreadsheets
- Presentations
- Images and photographs
- Text documents
If you are unsure whether a specific file type is permitted, please contact our support team for guidance.
Alternative File Transfer Methods
Email is primarily designed for communication rather than transferring potentially high-risk files.
If you need to send or receive restricted file types, we recommend using a dedicated file transfer solution instead.
File Transfer Services
Services such as WeTransfer allow large files to be uploaded securely and shared using a download link.
FTP / SFTP
FTP and SFTP services are specifically designed for transferring files between systems securely.
Website Downloads
Files can be uploaded to a website or secure portal and shared using a download link.
Cloud Storage
Platforms such as OneDrive, Google Drive, Dropbox, and similar services provide secure file sharing capabilities.
Need Assistance?
For security reasons, we do not publicly publish the full list of restricted file types.
If you need to verify whether a particular file type is permitted, or require advice on alternative ways to transfer files, please contact our support team and we will be happy to assist.