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Two Separate Routers (different networks ) from one modem


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#1 Bascotie

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Posted 09 July 2014 - 06:37 PM

Hi guys,

 

Now, I should mention I've set this up and it does work but it bugs me that I don't understand completely why.

 

I have a router/modem (all in one) that controls most of the computers here and then a cable from the LAN on the modem/router going to a different router on a different subnet (plugging into the WAN port on this separate router).

 

The first network (router/modem) is on 192.168.1.1

the second network (router alone) is on 192.168.0.1

 

Both have DHCP on, and the second router automatically sees the first as a DNS server and everything works.

 

Is this the proper setup, or can it create conflict/problems down the line? My goal is to keep both networks from communicating with each other while allowing both an internet connection. Thanks!



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#2 czarboom

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Posted 10 July 2014 - 01:28 AM

you did that fine.  This is because first network 192.168.1.1 devices will not talk to

192.168.0.1

 

as long as you do not put something on network 2, and give it a IP of 192.168.1.xxx you will be fine.

 

You did the subnetting correctly.


CZARBOOM 
 
"Never Stop Asking Questions, Question Your Environment, Question Your Government, above all Question Yourself.  We all lose when you Stop asking Why?

#3 Bascotie

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Posted 10 July 2014 - 12:21 PM

Thank you. So it's ok that both have their DHCP functions turned on?



#4 czarboom

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Posted 11 July 2014 - 11:30 PM

Yes, if you want the auto assigning of IPs then you have to have it on.  Just make sure the range you input is AT LEAST equal to the amount of devices you own.

 

What I mean is, say you use the IP range of 192.168.0.xxx (xxx being any number).  If you set a range of 100-110 so only IPs 192.168.0.100 to .110 will be allowed and you have 20 devices to connect then you will never get all connected only 10 at a time.

 

So if you have 20 devices make sure you have at least 20 IPs in that range.  If you don't know what I am talking about then don't worry, by default DHCP will use as many as it needs to get the job done.

 

good luck and let me know if you need anything else.

cz


CZARBOOM 
 
"Never Stop Asking Questions, Question Your Environment, Question Your Government, above all Question Yourself.  We all lose when you Stop asking Why?

#5 Orecomm

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Posted 13 July 2014 - 03:00 PM

Just a point of info, the setup you describe is "double NATting" the 192.168.0.x network. This setup MAY not work with some applications, such as some SIP (VoIP) services and some games. Generally, if you have to open ports in your router you would need to open the port in BOTH routers, with the 192.168.1.x router being configured to forward to the 192.168.0.x OUTSIDE (will be a 192.168.1.x) address, then the 192.168.0.x router to forward to the "real" service address on the 192.168.0.x network. This is not a common situation, but with some services and games it may pop up. If it works from 192.168.1.x and not from 192.168.0.x then that's what's most likely gotcha.

 

Also in this situation you will probably find that devices on the 192.168.0.x network CAN access devices on the 192.168.1.x network. To stop this you will need to block access to the 192.168.1.x network in the 192.168.0.x router. You may be able to do this with a firewall entry, or you may have to make a route entry to send 192.168.1.0/24 to somewhere "safe", like an unused address on the 192.168.0.x network.



#6 czarboom

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Posted 14 July 2014 - 12:54 AM

Good stuff all around.  The longer I spend not networking each day as a job, the more I forget. 

 

I would also say to advoid this, make the line from the first router to the second a static IP, and place it on a 10.10.xxx.xxx private to keep it separate logically and in your head


CZARBOOM 
 
"Never Stop Asking Questions, Question Your Environment, Question Your Government, above all Question Yourself.  We all lose when you Stop asking Why?

#7 Bascotie

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Posted 14 July 2014 - 01:07 AM

Thanks for all your help everyone. I think another frustration with setting up networks is that you're usually dealing with different routers all the time and it's not consistent.

 

Do most routers generally allow modification to all these settings?



#8 czarboom

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Posted 14 July 2014 - 01:49 AM

Most ones in the last 5 to 6 year will and do.  That is a very general rule, meaning some call their services different names, or require you to manage by LAN and not WiFi etc, etc.

 

A good way to start this is to write it down first.  I have been networking for 5 plus years, and I still write it down.  Its called a network phone book, and diagram, also called other things too.  But its a list of IPs, submasks, DNS, gateways etc on your network. 

The diagram, allows you to see the logical setup of your devices.

 

Or use a Network Simulator software like GNS3.net

It will allow you to place and setup your network as is in a interface, and test it.  It will also tell you where you are failing and sometimes tips on how to fix it.

 

Below is a total guide about managing networks etc.

 

Here is a Admin Total Routing Guide by CISCO.

 

Lastly if you confused about what and how many devices can be on your network and what ranges of numbers they fall under use an IP or Sub net calculator like this one here.

This will give you all the info you need, and cause you to fall asleep super fast. 

 

good luck

cz


CZARBOOM 
 
"Never Stop Asking Questions, Question Your Environment, Question Your Government, above all Question Yourself.  We all lose when you Stop asking Why?




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