Configuring a DHCP server in the dual and IPv6-only environments

Last Updated : Aug 28, 2026 |
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In the dual (IPv4 and IPv6) and IPv6-only environments, the phone acquires vendor-specific parameters, including the IP address of the file server, through DHCPv6 vendor-specific option 17. Use this procedure to set this option with an opt-code 242 to obtain an IPv6 address for the file server.
Before you begin
In the dual environment, install the DHCPv4 and DHCPv6 server software according to instructions provided by your vendor.
In the IPv6-only environment, install the DHCPv6 server.
  1. Depending on the environment, do one of the following:
    • In the dual environment, specify the IP address of the file server using DHCPv4.
    • In the IPv6-only environment, specify the IP address of the file server using DHCPv6.
  2. Configure the DHCPv6 server to send a Vendor-Specific Information (VSI) option with an enterprise number of 6889 which is the Avaya Enterprise Number.
  3. Include the vendor-specific option 17 with an opt-code of 242 within that option.
  4. Set the option-data portion of the vendor-specific option with the HTTPSRVR parameter.
The following shows an example of setting the vendor-specific option 17 in the dhcp6.conf file:## SSON on Avaya phone default is 242
## Specific the HTTP server used by the Avaya phones
 
## Allocate 2 bytes for option code, 2 bytes for option data length, 3 hash buckets
option space Avaya code width 2 length width 2 hash size 3;
option Avaya.avaya-option-242 code 242 = text;
 
## 6889 is enterprise number for Avaya
option vsio.Avaya code 6889 = encapsulate Avaya;
 
## option data (sample):
option Avaya.avaya-option-242 "HTTPSRVR=2000::114f:85f7:f238:9eb5,MCIPADD=2000::54,SIG=SIP";
Next steps
In the dual environment, it is recommended to set DUAL_IPPREF to
  • in the 46xxsettings.txt file.
    • This parameter is used only in dual mode to apply Site Specific Option Number (SSON) parameters either from a DHCPv4 or a DHCPv6 server.