ITPEC FE Morning April 2019 Question 34

Subnet Host Count — calculate max hosts from a subnet mask.

Subnet mask 255.255.255.224:

• •Last octet: 224 = 11100000 → 3 network bits, 5 host bits
• •Total addresses: 2^5 = 32
• •Usable hosts: 32 - 2 = 30 (subtract network and broadcast addresses)

Why not others:
- (a) 14 — corresponds to /28 mask (4 host bits: 2⁴ − 2 = 14)
- (b) 20 — does not correspond to any standard subnet mask
- (c) 26 — does not correspond to any standard subnet mask

Key rule: Max hosts = 2^n - 2, where n is the number of host bits. Subtract 2 for the network address and broadcast address.

AI-generated — may contain errors