What is the maximum number of option 150 IP addresses that a Cisco IP SCCP phone will accept and use from a DHCP server?
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A. B. C. D. E.B.
Cisco Unified IP Phones use the option 150 value as the TFTP server IP address when Alternate TFTP option is set to No.
You can assign only IP addresses as Option 150 values.
A maximum of two IP addresses get used, and only the first two IP addresses that the DHCP server provides get accepted.
References: http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/9_0_1/ccmsys/CUCM_BK_CD2F83FA_00_cucm-system-guide-90/ CUCM_BK_CD2F83FA_00_system-guide_chapter_01010.html.
Cisco IP SCCP phones use option 150 to obtain the IP address of their TFTP server from a DHCP server. This option is defined in RFC 5859 and is used by Cisco phones to locate their configuration files, firmware updates, and other files needed for operation.
When a Cisco IP SCCP phone requests an IP address from a DHCP server, it sends a DHCP option 150 request to the server. The DHCP server then responds with one or more IP addresses that the phone can use to locate its TFTP server.
The maximum number of option 150 IP addresses that a Cisco IP SCCP phone will accept and use from a DHCP server is two. This means that the DHCP server can respond with up to two IP addresses in the option 150 field, and the phone will use the first IP address listed as its TFTP server. If the first IP address is not available, the phone will use the second IP address listed.
Therefore, the correct answer to the question is B. 2.