OCS 2007 R2 introduced support for configuring a firewall to perform Network Address Translation (NAT) for the A/V Edge external interface. This option is available only with the Single Consolidated Topology as shown in figure 1.0. When configuring the A/V Edge for NAT it’s possible that remote users (both employees and federated) will be able to establish IM connectivity and view presence data but not escalate the conversation to an audio session. […]

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