10-31-2011 11:10 PM - edited 03-03-2019 06:24 AM
We provide ip address of 192.168.1.1/30 and 192.168.1.2/30 on WAN link between router A and router B. now if we try to provide 192.168.1.4/27 network to LAN of router A it shows same network IPs on both interfaces (i.e LAN and WAN). why is it so? The mask changes, the LAN ip segment is not same as given on WAN. Please someone explian this to me i'm confused.
11-01-2011 01:15 AM
Hi,
192.168.1.1/30 is from subnet 192.168.1.0/30 and 192.168.1.2/30 is from same subnet
192.168.1.4/27 is from subnet 192.168.1.0/27 so the LAN subnet overlaps with the WAN subnets because the LAN subnet comprises addresses from 192.168.1.1 to 192.168.1.30 and so the 2 WAN addresses.
Regards.
Alain.
11-01-2011 01:20 AM
Hi,
Thanks for responding!
so what would u suggest for LAN next to these 2 IPs, i.e after utilizing 192.168.1.1/30 and 192.168.1.2/30 on WAN.
regards
Roman
11-01-2011 10:46 AM
Hi,
you could use 192.168.2.x /27
Alain.
11-01-2011 02:44 PM
Alain provides a very easy and effective solution which is to start in a different /24 network. And this would certainly work. But I sense that Roman may be looking for a solution that would put both subnets into the same /24.
If that is the case then Roman needs to think through the question of what subnets are available in a /27 and which one are already used and which ones are available. A /27 uses a mask of 255.255.255.224 and the subnets and address ranges are as follows
subnet address range
192.168.1.0 192.168.1.1 through 192.168.1.31
192.168.1.32 192.168.1.33 through 192.168.1.63
192.168.1.64 192.168.1.65 through 192.168.1.95
192.168.1.96 192.168.1.97 through 192.168.1.127
192.168.1.128 192.168.1.120 through 192.168.1.159
192.168.1.160 192.168.1.161 through 192.168.1.191
192.168.1.192 192.168.1.193 through 192.168.1.223
192.168.1.224 192.168.1.225 through 192.168.1.255
Assignment of 192.168.1.1 as a /30 makes the first subnet used. But any of the other subnets could be available for use.
Perhaps the most logical thing would be to assign 192.168.1.32/27 as the subnet for the LAN since it is the next available subnet.
HTH
Rick
11-02-2011 10:38 PM
Thanks a lot Rick!
That was explained clearly.
Regards
Roman
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