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IP allotment on WAN and LAN

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.

5 REPLIES
Purple

IP allotment on WAN and LAN

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.

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New Member

IP allotment on WAN and LAN

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

Purple

IP allotment on WAN and LAN

Hi,

you could use 192.168.2.x /27

Alain.

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Hall of Fame Super Gold

IP allotment on WAN and LAN

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

New Member

IP allotment on WAN and LAN

Thanks a lot Rick!

That was explained clearly.

Regards

Roman

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