The document discusses data security in local networks using distributed firewalls. It describes how distributed firewalls work to overcome issues with traditional firewalls, which rely on a single entry point. Distributed firewalls are centrally managed from a network server but installed on endpoints throughout the network. This allows security policies to be defined and pushed centrally while filtering traffic both from the internet and internally. It also discusses how distributed firewalls use pull and push techniques to update endpoints with the latest security policies from the central management server.