AudioCodes Mediant 4000 SBC, User Manual

Page: 217 / 1037

CHAPTER 16 Services
Mediant 4000 SBC | User's Manual
16 Services
This section describes configuration for various supported services.
DHCP Server Functionality
The device can serve as a Dynamic Host Configuration Protocol (DHCP) server that assigns and
manages IP addresses from a user-defined address pool for DHCP clients. The DHCP server can
also be configured to supply additional information to the requesting client such as the IP address of
the TFTP server, DNS server, NTP server, and default router (gateway). The DHCP server
functionality complies with IETF RFC 2131 and RFC 2132.
The DHCP server can service up to 10,000 DHCP clients. The DHCP clients are typically IP
phones that are connected to the device's LAN port.
The DHCP server is activated when you configure a valid entry in the DHCP Servers table (see
Configuring the DHCP Server ) and associate it with an active IP network interface listed in the IP
Interfaces table. When an IP phone on the LAN requests an IP address, the DHCP server allocates
one from the address pool. In scenarios of duplicated IP addresses on the LAN (i.e., an
unauthorized network device using one of the IP addresses of the DHCP address pool), the DHCP
server detects this condition using an Address Resolution Protocol (ARP) request and temporarily
blacklists the duplicated address.
You can also configure the DHCP server to respond only to DHCPDiscover requests from DHCP
clients that contain a specific value for Option 60 (Vendor Class Identification). For more
information, see
Configuring the Vendor Class Identifier .
Configuring the DHCP Server
The DHCP Servers table lets you configure the device's DHCP server (only one). The DHCP
Server table configures the DHCP server implementation. This includes configuring the DHCP IP
address pool from where IP addresses are allocated to requesting DHCP clients, as well as
configuring other information such as IP addresses of the DNS server, NTP server, default router
(gateway), and SIP proxy server. The DHCP server sends the information in DHCP Options. The
table below lists the DHCP Options that the DHCP server sends to the DHCP client and which are
configurable in the DHCP Servers table.
Table 16-1: Configurable DHCP Options in DHCP Servers Table
DHCP Option Code DHCP Option Name
Option 53 DHCP Message Type
Option 54 DHCP Server Identifier
Option 51 IP Address Lease Time
Option 1 Subnet Mask
Option 3 Router
Option 6 Domain Name Server
Option 44 NetBIOS Name Server
Option 46 NetBIOS Node Type
- 184 -