Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series/CP860 IP Phones465. Press the Save soft key to accept the change.A dialog box pops up to prompt that the settings will take effect after a reboot.6. Click OK to reboot the phone.DHCP OptionDHCP provides a framework for passing information to TCP/IP network devices. Network andother control information are carried in tagged data items that are stored in the options field ofthe DHCP message. The data items themselves are also called options.DHCP can be initiated by simply connecting the IP phone with the network. IP phones broadcastDISCOVER messages to request the network information carried in DHCP options, and theDHCP server responds with specific values in corresponding options.The following table lists common DHCP options supported by IP phones.Parameter DHCP Option DescriptionSubnet Mask 1 Specify the client’s subnet mask.Time Offset 2 Specify the offset of the client's subnet in secondsfrom Coordinated Universal Time (UTC).Router 3 Specify a list of IP addresses for routers on theclient’s subnet.Time Server 4 Specify a list of time servers available to the client.Domain NameServer 6 Specify a list of domain name servers available tothe client.Log Server 7 Specify a list of MIT-LCS UDP servers available tothe client.Host Name 12 Specify the name of the client.Domain Server 15 Specify the domain name that client should usewhen resolving hostnames via DNS.Broadcast Address 28 Specify the broadcast address in use on theclient's subnet.Network TimeProtocol Servers 42 Specify a list of NTP servers available to the clientby IP address.Vendor-SpecificInformation 43 Identify the vendor-specific information.Vendor ClassIdentifier 60 Identify the vendor type.TFTP Server Name 66 Identify a TFTP server when the 'sname' field in
