Hackers often install webshells on onpatched Zimbra systems and then wait for some time before actually abusing the compromised system. Especially on systems where critical security patches where installed too late, it may seem all was OK, where in fact a hacker has already gained access to the system, but did not do any other […]
Archive | PowerTips – Admins
Configure Zimbra OpenDKIM to sign the Subject header
By default Zimbra OpenDKIM does not sign the Subject header. At this time the configuration of what headers are signed by Zimbra OpenDKIM cannot be done via zmprov. There is a pending feature request to make these headers configurable via zmprov. In this article you will learn how to configure Zimbra OpenDKIM by customizing the […]
Zimbra with Single Sign-On using Google Workspaces
In this article you will learn how to set-up Zimbra on Google Workspaces. Google Workspaces serves as a SAML Identity Provider (IdP) and Zimbra will be a SAML Service Provider (SP). The technology used in this article is SAML, an open standard for Single Sign-On. When using SAML an Identity Provider (IdP) will take care […]
Per user attachment size limits
Zimbra Postfix can be configured to use Postfwd. Postfwd can be seen as a firewall for Postfix and it allows the creation of rulesets to implement email restrictions. A new Admin UI Zimlet and extension leverage Postfwd to configure per user attachment size limits. More information and download is available on the Per user attachment […]
A Milter for using Spamhaus HBL with Zimbra Postfix
In this article you will learn how to use Spamhaus Hash Blocklist (HBL) to improve email protection in Zimbra. For a long time administrators of Zimbra have relied on Spamhaus to fight incoming spam by configuring Postfix using traditional blacklists. These traditional blocklists work by blocking IP (ranges) and domains of known spammers. When an […]
Improve email Zimbra protection with Spamhaus HBL
In this article you will learn how to use Spamhaus Hash Blocklist (HBL) to improve email protection in Zimbra. For a long time administrators of Zimbra have relied on Spamhaus to fight incoming spam by configuring Postfix using traditional blacklists. These traditional blocklists work by blocking IP (ranges) and domains of known spammers. When an […]