General Options

It allows the insertion of general DHCP parameters, which shall be attributed by default to the clients:

• Base domain: Domain where the DHCP is operating;
• DNS servers: DNS servers to be used by the DHCP server;
• NetBios servers: NetBios servers to be used by the DHCP server;
• Clients mask: Mask to be used by the clients of the DHCP service;
• Default lease time: Default lease time during which the 'lease' of the address is valid for the clients;
• Max lease time: Max lease time of an IP address for the machines. When this value is surpassed, the IP address is renewed.

If you want the DNS Dynamic Update, it is necessary to choose "Yes" in the respective box. This feature is used to update dynamically a machine's IP in the DNS record (if that machine is not registered with its MAC address).

Note: It is possible to visualize the leases of the DHCP at:
Advanced Configurations -> Support services -> DHCP -> DHCP Leases

Redundancy

It is possible for an IP network to configure two DHCP servers, one as main (primary) server and the other as secondary. Normally, only the primary server answers the requests, while the secondary one synchronizes its DB with the primary, if the primary fails the secondary shall assume its service. Communication between the servers is made from the network ports which may be customized. One of the ports shall be attending the connections from the secondary server and the other one shall be attending the connections from the main server. (Figure 7.37)