NAT
The NAT mode allows the subscriber to maintain a large network, while using up only one public IP address. The Aperto NAT implementation comes with the following capabilities:
- Uses Port Address Translation (PAT), to allow up to 254 hosts in the private network.
- The NAT SU can be configured to map selected applications (such as FTP, HTTP, SMTP, etc.) to selected hosts in the private network, thus enabling the subscriber to maintain public servers in the private network.
- The SU allows up to 16 different public IP addresses to be mapped to private IP addresses. This provides another mechanism to maintain public servers in the private network.
- The NAT SU includes a DHCP server for automatic assignment of the private addresses.
- If the NAT SU cannot map an incoming packet, then it automatically routes it to a default host in the private network. This host then becomes the server for all applications that have not been explicitly mapped.
- The NAT SU allows multiple IPSec or PPTP VPN sessions to originate in the private network (most other NAT routers do not support this).
- The NAT mode automatically acts as a firewall for incoming traffic, since it does not allow a session into the private network, unless it originated within it (the exceptions being the Accessible hosts.