Adding an ‘External’ Warning to Email Bodies in Proxmox Mail Gateway: A Simple Guide

If you want to add external warning on email subject, please read this one: Proxmox Mail Gateway : How to add “EXTERNAL” warning on email subject

ATTENTION: If you have a disclaimer on your PMG added in the footer, your disclaimer will be added in the header if you follow this guide

In this article, I am going to describe how to add external warning in the body of the email. This warning usually appears on the first line before the actual content

– Go to PMG Dashboard -> Mail Filter -> Action Objects
– Click Add and select Disclaimer
– Add information to the Name and Comment
– Fill in the Disclaimer column with the following lines

<div style="background-color: #ffeb9c; width: 100%; padding: 2pt; font-size: 10pt; line-height: 12pt; font-family: 'Calibri'; color: black; text-align: left; border: 1pt solid #9C6500;"><span style="color: #9c6500;">CAUTION:</span> This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender <span style="color: ##ff0000;">__SENDER__</span> and know the content is safe.</div>

– Go to PMG Dashboard -> Mail Filter – Click Add Rules
– Add information to the Name
– Fill 99 in the Priority
– Select in on Direction section
– Tick on the Active section

– Select Action Objects that has been created from Available Objects -> Action

Backup Disclaimer.pm file

cd /usr/share/perl5/PMG/RuleDB
cp Disclaimer.pm Disclaimer.pm-ori

Download new Disclaimer.pm file.

curl -k https://raw.githubusercontent.com/imanudin11/script/master/Disclaimer.pm > /usr/share/perl5/PMG/RuleDB/Disclaimer.pm

Restart pmg-smtp-filter

systemctl restart pmg-smtp-filter

Now, you can see the warning in the email body when receiving emails from the internet

Source html email template: https://github.com/leemunroe/responsive-html-email-template

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Good Luck 🙂