Windows Essential Business Server 2008 (EBS 2008) provides a Security Server as a part of integrated solution suite that provides integrated security. The technologies include Forefront Threat Management Gateway (Forefront TMG) and Edge transport role of Microsoft Exchange Server 2007 that’re installed on the Security Server. Organizations, partners, and administrators who want to integrate their Security Server in EBS 2008 into a network with an existing firewall now’ve a capability that enables a single-click reconfiguration of their Security Server to desired level. For information about different configuration changes made at each level, see Change Security Level, and about ways that Windows EBS 2008 helps secure a company's IT infrastructure, see Security and Protection in the Windows Essential Business Server Technical Library.
More info: EBS blog