In a perfect world, your Proxmox cluster always has an odd number of nodes, and everyone is talking to each other. In the real world, power outages happen, a NIC dies, or a 3-node cluster suddenly becomes a 1-node island of despair.
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Email Server Ports: A Comprehensive Guide to TCP and UDP Services
Email communication, a cornerstone of the internet, relies on a complex interplay of protocols and ports to ensure your messages reach their destination. Understanding these ports, their common names, and the security they offer is crucial for anyone managing an email server or simply curious about how email works. This article will delve into the essential TCP and UDP ports associated with email servers.
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Custom Fail2Ban Filters: A Step-by-Step Tutorial
Fail2Ban comes with many built-in filters for common services like SSH, Apache, and Postfix. But for custom applications, web apps (e.g., WordPress login attempts), or specific log patterns, you’ll need to create your own filters. This allows Fail2Ban to detect unique failure patterns and ban offending IPs automatically.
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