By setting up address translation in the NAT table, the networks and workstations become only visible under another address at first in the higher network compound. But for a seamless routing of data between the networks some further settings are still necessary:
- Entries in the routing tables for packets with new addresses to find the way to their destination.
- DNS forwarding entries, in order that inquiries about certain devices in the respective other networks can be resolved into mapped IP addresses.
- The firewall rules of the gateways must be adjusted such that (if necessary) authorized stations resp. networks from the outside are permitted to set up connections.
- VPN rules for loopback addresses in order to transmit the newly assigned IP addresses through an according VPN tunnel.
Note: The IP address translation takes place in the LANCOM between firewall
and IP router on one hand, and the VPN module on the other hand. All
rules related to the own network use therefore the “unmapped” original
addresses. The entries of the remote network use the “mapped” addresses
of the remote side, valid on the VPN connection.