Crucial Exams

Certified Ethical Hacker (CEH) Practice Question

While footprinting a target organization you have identified a publicly reachable host at 203.0.113.27. Before launching any active scans, you want to learn which other IP addresses are likely owned by the same company so you can plan a focused engagement. Which approach will most reliably reveal the entire CIDR netblock that has been allocated to this host without generating traffic toward additional target systems?

  • Send an oversized ICMP timestamp request to the host and use the returned TTL values to calculate the size of the organization's subnet.

  • Run a UDP scan against port 7 (Echo) on the host to capture replies that disclose the subnet mask and network size.

  • Perform a Whois query against the appropriate Regional Internet Registry to obtain the NetRange or CIDR information for 203.0.113.27.

  • Request the target domain's MX records from its authoritative DNS server to enumerate associated IP ranges.

Certified Ethical Hacker (CEH)
Reconnaissance Techniques
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