Cisco 200-301 Free Practice Questions — Page 3

Correct Answer: A. interface e0/0 description to XX-AXXX:XXXXX ip address 10.2.1.3 255.255.255.252

A /30 subnet uses the mask 255.255.255.252, providing only 2 usable host addresses per subnet, which is ideal for point-to-point links between two routers. Option A is the only choice using 255.255.255.252 (/30), making it the correct mask. Options B and C use 255.255.255.248 (/29), which provides 6 hosts and does not meet the /30 requirement. Option D contains a typographical error in the mask (225 instead of 255), making it invalid. A /30 subnet contains 4 total addresses: 1 network, 2 usable hosts, and 1 broadcast. The question focuses on identifying the correct /30 subnet mask, and option A is the only valid /30 configuration.

Correct Answer: B. 172.28.0.0/16

Private IPv4 address ranges as defined by RFC 1918 allow communication without needing public Internet addressing. The RFC 1918 private ranges are: 10.0.0.0/8, 172.16.0.0/12 (172.16.0.0–172.31.255.255), and 192.168.0.0/16. Option B, 172.28.0.0/16, falls within the 172.16.0.0/12 private range (172.16–172.31) and is therefore a private network. Option A, 172.9.0.0/16, is NOT within the private range (172.9 is outside 172.16–172.31) and is a public address. Option C, 192.0.0.0/8, is broader than the private 192.168.0.0/16 range and is not entirely private. Option D, 209.165.201.0/24, is a public address. Therefore, only 172.28.0.0/16 is a valid RFC 1918 private network.

Correct Answer: D. It is a broadcast IP address.

The exhibit shows the error 'Bad mask /28 for address 192.168.16.143'. The /28 mask (255.255.255.240) creates subnets of 16 addresses each. In the subnet 192.168.16.128/28, the addresses are: network 192.168.16.128, usable hosts .129–.142, and broadcast 192.168.16.143. The address 192.168.16.143 is the broadcast address of the 192.168.16.128/28 subnet. Cisco IOS rejects broadcast addresses when configuring an interface IP. This is not a private address issue (option A), the router fully supports /28 masks (option B), and .143 is not the network address (option C). The error occurs because the engineer attempted to assign the subnet broadcast address to the router interface.

Correct Answer: B. unique local

IPv6 unique local addresses (ULA, prefix FC00::/7) provide communication between subnets within an organization but are not routable on the public Internet, making them analogous to RFC 1918 private IPv4 addresses. Link-local addresses (FE80::/10) are restricted to a single link and cannot route between subnets at all. Multicast addresses are used for one-to-many delivery. Global unicast addresses (2000::/3) are publicly routable on the Internet. Unique local addresses begin with FD (the common usable range) and can traverse routers within a private network, but ISPs block them from the global Internet. Therefore, unique local is the correct IPv6 address type for inter-subnet communication that stays off the Internet.

Correct Answer: D. FF00::/8

IPv6 multicast addresses begin with the prefix FF00::/8, meaning any address starting with FF in the first octet is a multicast address. Multicast packets are sent to a group address, and all members of that group process the packet. Option A (2000::/3) is the global unicast range. Option B (FC00::/7) is the unique local address range. Option C (FE80::/10) is the link-local address range. Option D (FF00::/8) correctly identifies the IPv6 multicast address block where packets are sent to a group rather than a single unicast destination. The FF prefix is the definitive indicator of an IPv6 multicast address.