I have a LAN ( and want to separate clients (10.0.3.x) from the servers (10.0.0.x and 10.0.1.x) with a firewall in front of the servers. My problem is, i cant change address ranges nor subnets. Is this doable?


Edit: @HAL I looked up on vlsm and it looks exactly like what I need. Thank you.

  • Why can't you Variable Length Subnet?
    – HAL
    Mar 6, 2015 at 16:19

2 Answers 2


Variable Length subnetting is the process by which you'd divide up the LAN adress into segments.

I have a previous answer that may assist you in the task. You can find it here


No. The problem is that based on your subnet any devices on the network will bypass the default gateway and communicate directly with their peer. If you want to establish a DMZ in this manner, a subnet update on each client is mandatory.

  • 1
    Two words: Private Vlan Mar 9, 2015 at 9:06
  • Yeah, that would do it..., though an extra router is required. Mar 9, 2015 at 15:02
  • not really, put a firewall in bridge / transparent mode and set it up so the clients can only talk to the outside interface of the firewall Mar 10, 2015 at 8:12

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