Follow Jay in this two-part series as he goes over the fundamentals and configurations of High Availability. In part 1: Jay goes over the fundamentals and pre-requisites that you need to know before diving right into the configuration of High Availability. Afterward, check out Part 2, in which Jay covers how to configure both, QuickHA and Interactive Mode setup for High Availability using either Active-Active or Active-Passive.
Watch Part 1: https://techvids.sophos.com/watch/SndToy8TYMp7Tsfsa1CxKv
Watch Part 2: https://techvids.sophos.com/watch/CXgWk46RoUrF2MXQ4fqLQW
HA Pre-requisites: https://docs.sophos.com/nsg/sophos-firewall/18.5/Help/en-us/webhelp/onlinehelp/AdministratorHelp/SystemServices/HighAvailability/HAPrerequisites/index.html
Common High Availability Failover Triggers: https://docs.sophos.com/nsg/sophos-firewall/18.0/Help/en-us/webhelp/onlinehelp/HighAvailablityStartupGuide/AboutHA/HAOperation/index.html
High Availability Startup Guide: https://docs.sophos.com/nsg/sophos-firewall/18.0/Help/en-us/webhelp/onlinehelp/HighAvailablityStartupGuide/AboutHA/index.html
