Services; Dhcp Server Functionality; Configuring The Dhcp Server - AudioCodes Mediant 800B User Manual

User's Manual
15

Services

This section describes configuration for various supported services.
15.1

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 800 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'' on page 183) and associate it with an active IP
network interface (listed in the Interface 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'' on page 187.

15.1.1 Configuring the DHCP Server

The DHCP Servers table lets you configure the device's DHCP server. 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 15-1: Configurable DHCP Options in DHCP Servers Table
DHCP Option Code
Option 53
Option 54
Option 51
Option 1
Option 3
Option 6
Option 44
Option 46
Option 42
Option 2
Option 66
Version 6.8
DHCP Option Name
DHCP Message Type
DHCP Server Identifier
IP Address Lease Time
Subnet Mask
Router
Domain Name Server
NetBIOS Name Server
NetBIOS Node Type
Network Time Protocol Server
Time Offset
TFTP Server Name
183 Mediant 800B Gateway and E-SBC
15. Services