Jack is a network administrator at his organization. Last night he accidentally messed up the connections running to the server. Today all users have been complaining about not having Internet connectivity and IP addresses in the 169.254.xxx.xxx series. What should Jack check first?
Explanation
Answer: A -Jack should check the DHCP server or configurations. The 169.254 series of IP addresses is an APIPA-an IP address assigned when the computer is not able to obtain an IP address through DHCP.
Key Takeaway: The automatic private IP addressing (or APIPA) feature automatically assigns a 169.254.xxx.xxx address if the system does not obtain an IP address from the DHCP server at boot. When DHCP is not available, and a client workstation whose IP address is assigned by DHCP attempts to get its IP settings, APIPA allocates addresses in the private range 169.254.1.0 to 169.254.254.255, exclusive of the first and last 255 addresses. Clients verify their address is unique on the LAN by querying the other hosts using ARP and verifying that the address is not already assigned on the local network by another clients use of APIPA. When DHCP is available again, clients should update their addresses automatically, although sometimes they have to be forced to renew their DHCP settings manually. Any devices configured with APIPA use the default network mask 255.255.0.0 and are therefore all on the same subnet. This ensures that all devices configured in this manner on the same LAN can communicate with each other. APIPA is enabled on all DHCP clients in Windows by default, but can be disabled for the whole client or by individual network adapter.
