The Coral Sentinel Pro is a Session Border Control (SBC) unit that enables the connection of remote IP phones located behind NAT (Network Address Translation) servers or firewalls. It transfers signaling and RTP traffic through the firewall or NAT server to the relevant endpoints in the LAN network.
In standard operations, a firewall has to expose numerous holes in its defenses - one for each endpoint. For this purpose, the Coral Sentinel Pro maintains one defined access point to the firewall or NAT server, through which all incoming VoIP traffic is connected. Therefore, many separate IP phones can connect to the Internet via the firewall or NAT server, without the need to open up a separate channel to connect each call, as all incoming traffic is routed through one firewall-controlled channel to the Sentinel Pro. This also eliminates the need for VPN (Virtual Private Networking) software for VoIP devices connecting to the Sea Softswitch.

• Enables incoming traffic to be routed through a firewall, without the need to open up a permanent channel to transmit and receive calls
• Enables IP endpoints that are remotely located behind a NAT server to transverse the server
• Establishes local RTP sessions between remote MGCP IP endpoints located behind the same NAT server, thereby freeing up Sentinel RTP resources
• Provides secured connectivity for IP phones over the public Internet
• Protects against unauthorized access and prevents DoS (Denial of Service) and DDoS (Distributed Denial of Service) attacks