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I'm not a network guru. I have had this scenario a few times at a hackathon or small event for technical people. There are usually a group of 50-200 but with an average of anywhere up to 4 devices per person making it necessary to support anywhere up to 1000 devices over wifi. I usually have a few physical ports in the wall of an event space and a few home routers to play with.

The challenge is that there might only be a limited number of allocated ip addresses on the existing LAN usually in some sort of centralized set up, but usually not enough IP addresses for the number of devices being requested.

So finally my question: if the original network is on 192.168.1.0 can I set up a new network broadcast domain such as 172.16.0.0 etc using one of the routers and allocate enough ip numbers for devices. Essentially taking 1 IP allocated by the DHCP on the existing network and multiplying it into effectively 1000's of IP addresses in a new secondary private network space.

For example:

Setting up a DHCP for a new broadcast domain on top of the existing domain

  • Will this work?

Its possible that this scenario may work in certain circumstances but not others, or that it may work but with limited functionality, so for bonus points and to help understanding try breaking your answer down into these parts...

  • Is it ever possible to create a second private IP address space on top of an existing private IP address space (the new broadcast domain is separated from the public internet by another private network)?
  • Will devices on the second private network be able to access the public internet via the first existing network.
  • If this does work in practice, are there any scenarios where this does not work (i.e. 2 daisy chained private networks work but not 3)?
  • Unfortunately, questions about consumer-grade devices are explicitly off-topic here. You could try to ask about that on Super User. – Ron Maupin Jan 25 '19 at 6:00
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Short answer: Yes it'll work.

You can daisy chain multiple networks together as long as the routers are aware of each others Routing tables. Sort of.

Be careful though. Most of the routers you'll be working with have firewalls,nat, and so on. I suggest that you turn all that off in the second router and let the first router do all the security and such.

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  • Cool. Do I have to change the private IP address space i.e. 192 etc to 172 etc. Or can I just leave the DHCP on the second router (that I have access to) as default? – lindsaymacvean Sep 9 '15 at 13:11
  • Every network you add, it has to have a different ip address schema. For example you want 5 networks. You can do: 192.168.0.1/24 ... 192.168.1.1/24 .... 192.168.2.1/24 .... And so on – odannyc Sep 9 '15 at 13:39

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