List and Feed Updates for Security Intelligence
List and feed updates replace the existing list or feed file with the contents of the new file. Contents of existing and new files are not merged.
If the system downloads a corrupt feed or a feed with no recognizable entries, the system continues using the old feed data (unless it is the first download). However, if the system can recognize even one entry in the feed, it uses the entries it can recognize.
By default, each feed updates the Management Center every two hours; you can modify this frequency. Any updates the Management Center receives are passed immediately to managed devices. In addition, managed devices poll the management center every 30 minutes for changes. You cannot modify this frequency.
To modify feed update intervals, see Changing the Update Frequency for Security Intelligence Feeds.