186 CHAPTER 10: CONFIGURING IP T ELEPHONY■ Manually Assigned IP Settings — Use these fields to configure theIP settings for the telephone. You can change an IP setting only if thecorresponding field under IP Settings Reported by Device is 0.0.0.0. Ifthe field contains a value other than 0.0.0.0, you can change thevalue only through the telephone buttons. See the next section.Manually assigned settings take precedence over settings assignedautomatically by DHCP. If you manually enter the IP settings for atelephone, these settings replace any settings supplied by a DHCP server,and the telephone no longer searches for a DHCP server when it isplugged into a network.7 Click OK.The Ethernet (Layer 2) communications between the NCP and thetelephone ensure that the telephone receives the IP address of the NCP aspart of the configuration.You can program IP configuration directly into a telephone using thetelephone Local User Interface (LUI) utility. For the 3100 Entry Telephone,which does not have display panel, you can use the Telephone LocalConfiguration application. For detailed instructions on how to use thesetools, see the NBX Administrator’s Guide.AutomaticallyConfiguringTelephone IP SettingsWhen you connect a 3Com Telephone to a network, it searches for aDHCP server. If the telephone is on the same subnet as the NCP, thetelephone receives the following configuration information from theNCP:■ The IP settings (IP address, subnet mask, and default gateway address)for the telephone to use■ The IP address of the NCPThe telephone then stops searching for a DHCP sever.If a telephone is on a different subnet than the NCP and a DHCP serverprovides IP settings to the telephone, the telephone cannot communicatewith the NCP until it has the NCP IP address. There are two methods ofproviding the NCP IP address to the telephone:■ Manually configure the NCP IP address into the telephone using thetelephone LUI utility. See “Manually Configuring Telephone IPSettings” on page 185.■ Provide the IP address to the telephone using DHCP option 184. For anexample of how to configure option 184 on a DHCP server, see
