Connecting routers

KrisK91

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Nov 2, 2020
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Alright, question? I have the Xfinity XB7 connected as a gateway with no configurations done to it. I then have my Linksys EA7500 connected to the XB7 with an ethernet cord and configured to run as an Access Point. I would really like to be able to see which devices are actually connected through the Linksys EA7500. Is there a way to do is? I also have a TP Link C7 connected to the Linksys EA7500 router. I would really like to be able to have an range of IP address that would be used to assign devices to the TP Link C7.

Basically is there a way to assign devices on the Xfinity XB7 to have an IP range of 10.0.0.2 to 10.0.0.100
And have the Linksys EA7500 assign devices to have an IP range or 10.0.0.101 to 10.0.0.149
And have the TP Link C7 to assign devices to have an IP range of 10.0.0.150 to 10.0.0.200?
Or something along those line? Like I stated the Linksys EA7500 turns off all functionality when it is in AP mode which isn't an issue I would just like to know if when a certain device is connected to a specific device it will have an IP range depending on what it is connected to.

Because it doesn't matter if it is connected to the EA7500 or the TP Link C7 it still shows up on my XB7 of connected devices.

I also for some reason cannot find my printer on my network under connected devices. It's connected with a static IP address of 10.0.0.7 and when I go to the address it's online and running just fine I just can't seem to find it on my XB7 any ideas why this may be happening? The printer is connected to my Linksys EA7500.

Sorry if this is confusing, if it is I can try to clear this up a bit. I can include pictures to help understand what I am trying to accomplish.
 
Let me preface this with I do not have access to any of these devices. What I am going to say is generic.

1. If the Linksys is in AP mode then it should not be handing out addresses. The XB7 should be doing that. An AP is a layer 2 wifi to ethernet bridge.
2. I am assuming you are using 255.255.255.0 as your netmask ie /24 network. This means all of the ranges you specified are on the same network. You shouldn't be
3. You go off the rails when you say you want to plug the TPLink into the Linksys ROUTER. Is the Linksys in AP mode or not?


I briefly looked at your other thread a few days ago and assume this is related. What you should do is this.

1. Forget the Xfinity gateway .. get a bridge mode cable modem
2. Get a real wired router with the ability to IP multiple interfaces (not something you'll find at BestBuy)
3. IP the interfaces from the above with separate networks and configure DHCP pools for each
4. Plug separate switches in each of the above configured interfaces
5. From the this forward treat each switch separately as if it has nothing to with the rest the environment because without rules and routing on #2 it will be
6. If you need wireless go get some real AP (think ubiquti) and plug them into the switches keeping in mind they are separate.

If none if this makes sense then you just need to pay someone to set this up for you.

edit .. picture worth a thousand words.

PS: I should have labled each line from fw to switches with networks .... 10.0.1.0/24 and 10.0.2.0/24 and 10.0.3.0/24

This solves double NAT issues (there is no double nat here) and give you control over what can talk to what
 

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I'm not looking to put more money into stuff I already have. I don't really like having to rent a modem from Xfinity. But I don't seem to have issues with the XB7 and seems to work fine as a gateway. I just would like to be able to connect both the Linksys EA 7500 and the TP Link C7 into the XB7 and everything can see each other. I'm just trying to set it up all correctly. When I have both routers connected to the XB7 is the XB7 what is handing out IP address? I would really like to see an IP address and know which device it is connected to without having to dig and find out. Any simple way to do this without creating a Double NAT?
 
I'm not looking to put more money into stuff I already have. I don't really like having to rent a modem from Xfinity. But I don't seem to have issues with the XB7 and seems to work fine as a gateway. I just would like to be able to connect both the Linksys EA 7500 and the TP Link C7 into the XB7 and everything can see each other. I'm just trying to set it up all correctly. When I have both routers connected to the XB7 is the XB7 what is handing out IP address? I would really like to see an IP address and know which device it is connected to without having to dig and find out. Any simple way to do this without creating a Double NAT?
If the xfinity box is acting as the router and the linksys and tp link are both set to ap mode, all devices should be able to see each other.
 
Any simple way to do this without creating a Double NAT?
No ... either the network is flat and they all share the the same network managed by a single a DHCP server or you double nat or go the correct way and do it like I said.

I will add that with the double nat method all devices would not be able to see each other also.
 
Why would I not be able to have DHCP enabled on all my devices? And just have the Xfinity gateway to assign IP address from 10.0.0.2 to 10.0.0.99 and the Linksys router to assign IP addresses from 10.0.0.100 to 10.0.0.199 and the TP Link to assign IP addresses from 10.0.0.200 to 10.0.0.249?
Would that not work?
 
Why would I not be able to have DHCP enabled on all my devices? And just have the Xfinity gateway to assign IP address from 10.0.0.2 to 10.0.0.99 and the Linksys router to assign IP addresses from 10.0.0.100 to 10.0.0.199 and the TP Link to assign IP addresses from 10.0.0.200 to 10.0.0.249?
Would that not work?
No, it won't. You will have an IP address conflict if more than one DHCP server is running on the same subnet.
 
Having multiple DHCP servers on a single broadcast domain creates a race condition. Google the words you don't understand.
 
Why not just put the xb7 into bridge mode and do everything off of you linksys?
 
Yes, you can have more than one DHCP server within a subnet/VLAN as long as the scopes do not overlap.

In fact, it's a potential resiliency scenario because if one DHCP server was to fail then others will still provide an IP address.

That said, it also adds administrative complexity because you've then got multiple places to review DHCP leases.

The reality however is that in your scenario with a single Layer 2 broadcast domain (e.g. one subnet one VLAN) you would want to have one DHCP server.

In this case your configuration where the XB7 is assigning IP addresses and the C7 and EA7500 are in L2 bridge mode is 'correct'.

In business environments (e.g. Cisco Meraki) there are scenarios where the wireless access point(s) will assign DHCP addresses to clients and use NAT but this isn't applicable here.

Also, if you've set a static IP address on the printer then this isn't going to show up in the DHCP clients list on the XB7.

What you could do is remove the static IP address configuration from the printer, and then set up a DHCP reservation for that device MAC address to be assigned that IP (on the XB7).

You would of course however need to ensure that IP address is within the DHCP scope of the XB7 in the first place.
 
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