DHCP options for NEC DT-series phones

Spent some time learning how to configure DHCP options presented to NEC DT700 and DT800 series phones.  Perhaps this will be helpful for someone else.  Check out KB article 123518 to learn how to add/edit DHCP options (using the CLI).

Option 120 is not defined by default. Use the console to create the option so that it can be defined in a given DHCP pool:

console > system dhcp dhcp-options add optioncode 120 optionname SIP-Server optiontype array-of one-byte

Also, it is commonly recommended to disable SIP ALG (application layer gateway), called the SIP Module in XG Firewall, when VoIP systems are used.  In my experience, it's important to disable the SIP Module when NEC phones are used in your network. KB article 123523 provides instructions for disabling the SIP Module (SIP ALG) in XG Firewall.

SV8000/SV9000 Systems

console > system dhcp dhcp-options binding add dhcpname Phone_Network optionname Vendor_Encapsulated_Options(43) value a8:02:13:d8

console > system dhcp dhcp-options binding add dhcpname Phone_Network optionname SIP-Server(120) value 01,192,168,7,10

Notes:

• Option 43 presents SIP port UDP/5080 in hex format
  • A8 = sub-option 168
  • 02 = two bytes follow
  • 13 D8 = 5080
• Option 120 presents SIP server
  • 01 = IPv4 address follows
  • 192,168,7,10 = 192.168.7.10 (example SV SIP server address)

UNIVERGE 3C Systems

console > system dhcp dhcp-options binding add dhcpname Phone_Network optionname Time_Offset(2) value 4294949296

console > system dhcp dhcp-options binding add dhcpname Phone_Network optionname Time_Servers(4) value 192.168.1.1

console > system dhcp dhcp-options binding add dhcpname Phone_Network optionname TFTP_Server_Name(66) value "ftpserver.exampledomain.com"

console > system dhcp dhcp-options binding add dhcpname Phone_Network optionname SIP-Server(120) value 01,192,168,8,10

Notes:

• Option 2 presents time zone offset (Eastern in this example)
• Option 4 presents time server
• Option 66 presents FTP boot server
• Option 120 presents SIP server
  • 01 = IPv4 address follows
  • 192,168,8,10 = 192.168.8.10 (example 3C SIP server address)