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This article gives a quick overview of the Neighborcast feature in the F-Secure Automatic Update Agent (AUA), and also provides detailed information on its download logic.
Neighborcast is configured via three options:
- Neighborcast client (enabled/disabled) - controls whether the client tries to locate updates from clients in the same LAN.
- Neighborcast server (enabled/disabled) - controls whether the client listens and responds to neighborcast queries and offers updates for download.
- Neighborcast port - port used for neighborcast UDP queries.
When neighborcast is enabled, the client
- gets a list of available updates from Policy Manager Server (PMS)/Automatic Update Server (AUS)
- makes the decision to download an update
- sends a neighborcast query via broadcast UDP packet over the configured neighborcast port
- receives a unicast UDP reply back from other clients having the update
- picks a suitable peer and sends it a unicast UDP 'open session'
- after a positive confirmation, proceeds to download files over HTTP directly from the selected peer
- after downloading all the files, terminates the neighborcast session
- checks the received files against MD5 hashes and downloads any missing or corrupted files from PMS/AUS.