Match each description with an appropriate IP address. (Not all options are used.)
a private address
a loopback address
an experimental address
a TEST-NET address
a link-local address
64.102.90.23
169.254.1.5
192.0.2.123
240.2.6.255
172.10.20.5
The Correct Answer and Explanation is:
Sure! Here’s the matching of each description to the appropriate IP address:
Matches:
- a private address: 172.10.20.5
- a loopback address: (none of the given addresses match this)
- an experimental address: 240.2.6.255
- a TEST-NET address: 192.0.2.123
- a link-local address: 169.254.1.5
- 64.102.90.23: (none of the categories fit this address)
Explanation:
IP addresses are categorized into various classes and special-purpose ranges based on their intended use. Let’s break down each option and why it matches (or does not) the given descriptions.
1. Private address:
Private IP addresses are reserved for use within private networks and are not routable on the public internet. The common private IP address ranges are:
- 10.0.0.0 to 10.255.255.255
- 172.16.0.0 to 172.31.255.255
- 192.168.0.0 to 192.168.255.255
The address 172.10.20.5 falls within the 172.0.0.0 to 172.15.255.255 range, which is not private. The private range is specifically 172.16.0.0 to 172.31.255.255. Therefore, 172.10.20.5 is not private. So this option is a bit tricky: it’s close but outside the private range.
Reconsidering, the private addresses among these options are actually none, because 172.10.20.5 is outside the private range.
Let’s reanalyze the given options with accurate ranges:
- 169.254.1.5 is in the range 169.254.0.0/16, which is link-local.
- 192.0.2.123 is in the 192.0.2.0/24 block reserved for TEST-NET (documentation and examples).
- 240.2.6.255 falls within 240.0.0.0/4, which is reserved for experimental or future use.
- 64.102.90.23 is a regular public IP, not private, link-local, experimental, or loopback.
- Loopback addresses are in the range 127.0.0.0/8 (e.g., 127.0.0.1), none provided here.
Private addresses from the options? None exactly fit the private ranges. So none of the addresses provided qualify as private.
Corrected Matching:
- a private address: None provided (172.10.20.5 is outside the private range)
- a loopback address: None provided
- an experimental address: 240.2.6.255
- a TEST-NET address: 192.0.2.123
- a link-local address: 169.254.1.5
- 64.102.90.23: Public address, none of the above
Detailed explanation of these special IP address categories:
Private addresses are used for internal networks and cannot be routed on the public internet to protect network security and reduce global IP address consumption. The three ranges are:
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/16
Since 172.10.20.5 is outside the 172.16.0.0 to 172.31.255.255 range, it is not private.
Loopback addresses are used by a device to communicate with itself. These addresses are in the 127.0.0.0/8 range, most commonly 127.0.0.1.
Experimental addresses are in the range 240.0.0.0 to 255.255.255.254 (excluding 255.255.255.255). These are reserved for future use and generally not assigned publicly.
TEST-NET addresses (192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24) are reserved for documentation and examples. They never appear on the public internet.
Link-local addresses (169.254.0.0/16) are automatically assigned when DHCP fails, allowing devices on the same network segment to communicate without a DHCP server.
Public addresses like 64.102.90.23 are routable on the internet and don’t fall into any special reserved category.
Summary table:
| Description | IP Address | Reason |
|---|---|---|
| Private address | None | 172.10.20.5 is not in private range |
| Loopback address | None | No 127.x.x.x address provided |
| Experimental address | 240.2.6.255 | Falls in 240.0.0.0/4 reserved range |
| TEST-NET address | 192.0.2.123 | Reserved for documentation/examples (TEST-NET) |
| Link-local address | 169.254.1.5 | In 169.254.0.0/16 link-local range |
| Public (no category) | 64.102.90.23 | Regular public IP, no special categor |