1

Network Diagram:

network diagram

I got 3 vlans

1st Management

Required hosts: 15

Network ID: 192.168.100.0/27
Range : 192.168.100.0/27 - 192.168.100.31/27
Highest IP default-gateway: 192.168.100.30/27

2nd USER

Required hosts: 70

Network ID: 192.168.100.32/25
Range : 192.168.100.32/25 - 192.168.100.159/25
Highest IP default-gateway: 192.168.100.158/25

3rd Guest

Required hosts: 10

Network ID: 192.168.100.160/28
Range : 192.168.100.160/28 - 192.168.100.176/28
Highest IP default-gateway: 192.168.100.174/28

So in Level 1 switch I put IP default-gateway: 192.168.100.30

So in Level 2 switch I put IP default-gateway: 192.168.100.30

On router:

f0/1.99 IP : 192.168.100.30/27

f0/1.10 IP : 192.168.100.158/25

f0/1.20 IP : 192.168.100.174/28

It doesnt work.

error: 192.168.100.160 overlaps with FastEthernet0/1.10

So what I am doing wrong ?

2
  • 1
    Sounds a lot like a homework question...
    – Ricky
    Jun 5, 2014 at 5:13
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 7, 2017 at 22:36

1 Answer 1

6

You have overlapping subnets. You can't assign the subnet ID at random, it's a function of the mask. Valid subnet ID's for 192.168.100.X/25 are either 192.168.100.0 or 192.168.100.128

The IP Address 192.168.100.158/25 is part of the 192.168.100.128/25 subnet with valid IP addresses from 192.168.100.129-254

To avoid overlap, use these subnets:

192.168.100.0/25
192.168.100.128/27
192.168.100.160/28
2
  • BUt this is how I learn that use the next network ID : 192.168.100.32/25 after that use the netxt network ID : 192.168.100.160/
    – k31453
    Jun 5, 2014 at 2:55
  • 2
    @k31453 That only works if your using the same subnet mask, or if you're increasing the prefix length. Jun 5, 2014 at 5:04

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