Overlapping VLSM Subnets – Speed Test 1
By certskills
It’s subnetting Friday – #CCENT edition. Your job? Look at a set of 5 or 6 subnet/mask combos, and identify which ones overlap, and which ones do not. There may be no overlaps, or there may be a lot.
Not sure what I mean? Look at the following post first, which puts it in perspective, and then come back here.
The Problem Statement
Identify which subnets overlap with each other. That is, if the subnets listed as #1 and #2 in the list overlap, list “1&2” as your answer.
- 10.25.64.0/20
- 10.25.99.96/30
- 10.25.48.0/21
- 10.25.88.128/25
- 10.25.96.0/22
- 10.25.46.0/23
By certskills
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1. 10.25.64.0/20: 10.25.64.0 – 10.25.79.255
2. 10.25.99.96/30: 10.25.99.96 – 10.25.99.99
3. 10.25.48.0/21: 10.25.48.0 – 10.25.55.255
4. 10.25.88.128/25: 10.25.88.128 – 10.25.88.255
5. 10.25.96.0/22: 10.25.96.0 – 10.25.99.255
6. 10.25.46.0/23: 10.25.46.0 – 10.25.47.255
Answer: 2 & 5 overlap
Howdy! Thanks for playing. I’ll post the answers post in a few days, with explanation. I’ll withhold a confirm/reject of your answer til then, to avoid spoiling for any others while they’re still working. Thanks!
10.25.64.0/20———-00001010.00011001.01000000.00000000/20
11111111.11111111.11110000.00000000
10.25.64.0
10.25.79.255
10.25.99.94/30———00001010.00011001.01100011.01011110/30
11111111.11111111.11111111.11111100
10.25.99.92
10.25.99.95
10.25.48.0/21———-00001010.00011001.00110000.00000000/21
11111111.11111111.11111000.00000000
10.25.48.0
10.25.55.255
10.25.88.1/25———-00001010.00011001.01011000.00000001/25
11111111.11111111.11111111.10000000
10.25.88.0
10.25.88.127
10.25.96.0/22———-00001010.00011001.01100000.00000000/22
11111111.11111111.11111100.00000000
10.25.96.0
10.25.99.255
10.25.46.0/23———-00001010.00011001.00101110.00000000/23
11111111.11111111.11111110.00000000
10.25.46.0
10.25.47.255
answer:10.25.99.96/30 and 10.25.96.0/22 overlaps
3 $ 6
A) 10.25.64.0/20 x
10.25.0100-0000.00000000 10.25.64.0/20
10.25.0100-1111.11111111 10.25.79.255/20
B) 10.25.99.96/30 <————————–
10.25.01100011.011000-00 10.25.99.96/30
10.25.01100011.011000-11 10.25.99.99/30
C) 10.25.48.0/21 x
10.25.00110-000.00000000 10.25.48.0/21
10.25.00110-111.11111111 10.25.55.255/21
D) 10.25.88.128/25 x
10.25.01011000.1-0000000 10.25.88.128/25
10.25.01011000.1-1111111 10.25.88.255/25
E) 10.25.96.0/22 <————————–
10.25.011000-00.00000000 10.25.96.0/22
10.25.011000-11.11111111 10.25.99.255/22
F) 10.25.46.0/23 x
10.25.0010111-0.00000000 10.25.46.0/23
10.25.0010111-1.11111111 10.25.47.255/23
answer B – E.