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Difficulty: HardMobile Device Wireless and Network Connectivity

A logistics supervisor using a corporate tablet in a warehouse loses connection to internal server applications while moving between loading docks. Network diagnostics show the tablet currently has an IPv4 address of 169.254.14.92169.254.14.92 with a subnet mask of 255.255.0.0255.255.0.0. Cellular connectivity on the device is disabled by company policy. Which of the following best explains why the tablet lost access to the internal network?

  1. The tablet failed to reach a DHCP server on the wireless network and self-assigned an Automatic Private IP Addressing (APIPA) address.Answer
  2. B
    The tablet's International Mobile Subscriber Identity (IMSI) was invalidated when roaming between wireless access points.
  3. C
    The tablet attempted to synchronize network credentials using POP3 on port 110 instead of IMAP on port 993.
  4. D
    The wireless access points were misconfigured to use non-overlapping 2.4 GHz channels 1, 6, and 11.

Answer

The tablet failed to reach a DHCP server on the wireless network and self-assigned an Automatic Private IP Addressing (APIPA) address.
An IP address starting with 169.254 indicates Automatic Private IP Addressing (APIPA). When a mobile device fails to obtain an IP lease from a DHCP server on a wireless network, the OS automatically self-assigns an APIPA address. Because APIPA addresses do not include default gateway information, the tablet loses access to internal corporate subnets and server applications.

Step-by-Step Solution

1
Analyze the assigned IP address string
The IP address 169.254.14.92169.254.14.92 falls within the 169.254.0.0/16169.254.0.0/16 network block.
Addresses within 169.254.0.1169.254.0.1 to 169.254.255.254169.254.255.254 are reserved for Automatic Private IP Addressing (APIPA).
2
Determine the root cause of an APIPA address assignment
APIPA is automatically configured by the client operating system when DHCP discovery fails.
When a mobile device cannot contact a DHCP server or receive a response to its DHCPDISCOVER request, it assigns itself an APIPA address.
3
Evaluate the impact on local network connectivity
APIPA addresses allow communication only with other APIPA hosts on the same local broadcast domain and cannot route to internal corporate servers or external networks.
Without a default gateway and valid local subnet IP issued by DHCP, network access beyond the local link is broken.

Key Concept

APIPA Address Recognition and DHCP Failure Diagnosis
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Topics

Mobile Device Wireless and Network Connectivity

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