CyberCertPrepNetwork FundamentalsIP Addressing & SubnettingEASYFree question
What is a /29 subnet, and how many usable host addresses does it provide? Give an example of a use case.
- A./29 = 255.255.255.248, 8 total addresses, 6 usable hosts - useful for small branch LANs, printer clusters, or server groups needing a dedicated subnet with minimal address waste
- B./29 = 255.255.255.252, 4 total addresses, 2 usable hosts - used for point-to-point WAN links
- C./29 = 255.255.255.240, 16 total addresses, 14 usable hosts
- D./29 provides 29 usable host addresses by definition
Why A is correct
/29 mask = 255.255.255.248 (binary: 11111111.11111111.11111111.11111000). Host bits = 3. Total addresses = 2^3 = 8. Usable hosts = 8 − 2 = 6 (subtract network and broadcast). Block size = 256 − 248 = 8. Example: a DMZ with 3 servers needs a /29 subnet - 6 usable addresses provide room for the servers plus a gateway and some growth. Contrast with /30 (2 usable hosts for WAN links) and /28 (14 usable hosts).
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