You will see something like: origin: AS15169 (Google’s ASN). Zimbra does not have a GUI for ASN filtering, but you can configure Postfix directly.
Edit /opt/zimbra/common/conf/postfix_asn_blacklist Add the ASN netblocks (you must expand ASN to CIDR ranges manually or via script): asn zimbra
If you have searched for "ASN Zimbra," you are likely trying to solve one of two problems: or Network security (rate limiting) . Here is what ASN means in the context of Zimbra and how to manage it. What is an ASN? ASN stands for Autonomous System Number . It is a unique identifier assigned by global authorities (IANA/RIRs) to a network or collection of IP addresses owned by an organization (e.g., Google, AWS, or a local ISP). You will see something like: origin: AS15169 (Google’s
# Install a lookup tool (Ubuntu/Debian) apt install whois whois 8.8.8.8 | grep -i origin Here is what ASN means in the context
postmap /opt/zimbra/common/conf/postfix_asn_blacklist
Since "ASN" can refer to several technical concepts (Autonomous System Number, Application Service Node, or an education provider like ASN), this article covers the most common and technically relevant scenarios for IT administrators and engineers. In the world of email server management, particularly for administrators handling Zimbra Collaboration Suite (ZCS) , logs and headers often present cryptic acronyms. One such term that frequently appears in mail logs, firewall rules, or anti-spam configurations is ASN .