Archive | PowerTips – Admins

Two Thirds of Fortune 500 Companies Miss The Mark On Email Security … Do You?

This week, Axios reported … Fortune 500 companies are doing … a lousy job at email security. 330 out of the Fortune 500 companies do not have computers set up to prevent sending fraudulent emails in a firm’s name. If these resource-rich companies have not implemented simple steps to beef up their email security, chances are that […]

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Zimbra Admin Alert … Potential “memcrashd” attack

Zimbra memcached may face the “memcrashd” attack on port 11211. By default, memcached listens on a server IP address that is accessible on the network and via the internet if there is no firewall. If your Zimbra memcache servers are behind a firewall, we recommend blocking access on port 11211 from the Internet to Zimbra […]

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How to Install Zimbra Collaboration 8.8 on Ubuntu 16.04 LTS

Greetings, Everyone. In this blog post we will cover the installation of the latest Zimbra Collaboration 8.8 Network Edition release on Ubuntu 16.04 LTS, using dnsmasq as a DNS Server. These steps cover a single-server installation. If you are looking for multi-server installation steps, please visit our official guide. This blog post is a bit […]

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How to Reduce Incoming SPAM and MTA Overload using Postscreen

Zimbra Postscreen, availabile starting with Zimbra Collaboration 8.7, provides additional protection against mail server overload. One postscreen process handles multiple inbound SMTP connections and decides which clients may talk to a Post-fix SMTP server process. By keeping spambots away, postscreen leaves more SMTP server processes available for legitimate clients and delays the onset of server overload […]

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How to block incoming users or domains

Hello everyone, Zimbra Collaboration includes anti-SPAM and antivirus technologies such as Postscreen, Spamassasin, Amavis, ClamAV, etc. But sometimes, for legal reasons, etc., we need to block certain senders or even entire domains from sending unsolicited email. To do this, we will use the tools that come native to Zimbra Collaboration, and with a few simple […]

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