Custom Exim Filter Examples

cPanel allows you to easily create custom Exim filters by simply dropping the rules in /usr/local/cpanel/etc/exim/sysfilter/options/ and running: /scripts/buildeximconf service exim restart Here are a couple useful examples of filters we’ve created for our customers: Prevent email delivery to certain domains: if (“$h_to:, $h_cc:” contains “@domain.com”) or (“$h_to:, $h_cc:” contains “@domain.com”) then fail text “Emails to…

Read more

Resolving MS15-055 on cPanel Servers

If you’re a hosting provider with cPanel servers that were set up prior to version 11.46, you may be hearing from customers using Outlook ever since MS15-055 was released by Microsoft on May 12.  This most recent Outlook upgrade prevents the software from connecting to a POP or IMAP server that uses DH keys that are…

Read more

Configure Email Client Shows Wrong SSL Hostname

CPanel allows you to install a shared SSL certificate for email services so your users can connect securely to POP, IMAP, and SMTP.  The only real drawback here is that you can only natively use one certificate, which means your users should be connecting to the correct hostname under which the SSL certification is installed from…

Read more

Implementing Mandrill with Exim on cPanel

Mandrill is a transactional email service run by MailChimp, comparable to SendGrid.  It comes stock with a powerful API for fast implementation into applications for sending email reliably over SMTP, but it can also be used as a smart host for all of your server’s outgoing email. The below instructions cover how to do this…

Read more

Implementing SendGrid with Exim on cPanel

Updated 3/9/21 Setting up your cPanel server to send through a third-party mail server is very easy to do, if you understand the basics of how cPanel builds its Exim configs. You never want to edit your exim.conf file directly – your changes will be wiped out any time a cPanel update runs or someone…

Read more

Exim Privilege Escalation in 4.69-23

The cPanel security team found an issue in Exim that can potentially allow a user on the system to potentially run commands as the root user. Luckily, cPanel has already released a patch which is available for immediate download via their Exim upgrade script. If your system is set to update cPanel automatically, you may…

Read more

Log in