The Dynamic Host Configuration Protocol (DHCP) provides an administrator with a framework for passing configurations to DHCP clients on a network. DHCP Options are added configuration parameters that a DHCP server pushes out to DHCP clients. When the DHCP server receives the DHCPREQUEST message from the client, the configuration process enters its final phase. The acknowledgement phase involves sending a DHCPACK packet to the client.
Dynamic Host Configuration Protocol (DHCP) allows a client device to automatically obtain the information for services and configuration necessary to operate on a given network. To initiate this protocol, the client first sends out a broadcast packet called a DHCP Discover, contextualized below.
Many organizations use the MX appliance as a DHCP server, which will also configure hosts to use a specific DNS server. The MX offers four options for which DNS servers will be used:
The MX Security Appliances and MS Layer 3 Switches have a DHCP feature that controls IP Address leases and lengths. DHCP leases can be set for varying periods of time up to 1 week. Client machines will renew their lease early, which is expected behavior.
When deploying Cisco Phones and Call Manager, it may be desirable for the phones to automatically discover the TFTP server/Call Manager in order to download a configuration. This will happen automatically when phones are in the same broadcast domain as the Call Manager Server. However, if your Call Manager server is in a different network, you may need to specify a TFTP server. This article explains how to specify a TFTP server using DHCP options.
