1 LAN, 2 Routers - each with dedicated AP

Toggle sidebar Toggle sidebar
G

Grubby66

Commendable
Aug 30, 2016
4
0
1,510
After much searching I'm slightly more confused than when I started! If anyone can point me in the right direction I would be very grateful.

I have a 192.168.1.0/24 LAN, Cisco SRP527 router providing DHCP, mostly wired devices on a Netgear switch (factory defaults), with an AP(1) for the odd wireless device, all worked fine.

The DSL however was very slow so I added a 4G router (turned off it's DHCP) and then pointed a couple of the wired devices at it, i.e. to use it as their default gateway as it's about 30x faster than the DSL. All was well.

Then I had the not so bright idea of adding another AP(2), different SSID, and just to point at the 4G router. But as it's DHCP feature is off when I connect to that AP(2) it still picks up an IP address from AP(1) and uses the DSL router as it's gateway. The 4G router has a data cap and isn't cheap so it's not for general use, hence the need for a seperate AP. Plus I need to be able to see all the other devices on the LAN and when I set up two VLAN's on the switch I couldn't.

Can what I'm attempting even be done or do I need a managed AP setup? I’m not necessarily after the answer, just to be pointed in the right direction!

Many thanks,

G
 
Solution
B
The simplest although painful way would be to manually change the gateway ip on the devices that connect via the second ssid.

If the dhcp server has the ability you can set different gateways based on the mac. Most router based ones are lucky if you can put in static ip to mac mappings and do not have the option for a gateway. A small pc based DHCP server would have that option. It is still a form of manually hard coding the gateway though just in a central location. It can not tell where the request came from.

Your largest issue is there really is no way to tell where traffic is coming from. Even the second router may not have the ability to know if the traffic is coming from the wireless radio chip or the lan chip.

A very...
Sort by date Sort by votes
B

bill001g

Titan
Aug 9, 2012
28,319
2,754
125,640
The simplest although painful way would be to manually change the gateway ip on the devices that connect via the second ssid.

If the dhcp server has the ability you can set different gateways based on the mac. Most router based ones are lucky if you can put in static ip to mac mappings and do not have the option for a gateway. A small pc based DHCP server would have that option. It is still a form of manually hard coding the gateway though just in a central location. It can not tell where the request came from.

Your largest issue is there really is no way to tell where traffic is coming from. Even the second router may not have the ability to know if the traffic is coming from the wireless radio chip or the lan chip.

A very non standard way to fix this is to filter dhcp packets. You would need either your router or your switch to be able to block DHCP requests on the port connecting your second router to the switch. You could then run dhcp on the second router for devices directly connected to it or connected via wireless. Careful planning of the DHCP scope on both routers would prevent interference. Still the ability to filter traffic on lan or switch ports is not common on consumer grade equipment. It tends to be more common as you get more advanced switches though.
 
Upvote 1 Downvote
Solution
G

Grubby66

Commendable
Aug 30, 2016
4
0
1,510


Yep - completely agree. Tried this and whilst it works it's a pain. I didn't want to use MAC filtering because one day I might want a device to connect to AP(1) and then the next to AP(2), and filtering DHCP requests is way beyond my sphere of knowledge at this time!

I think I need to:
a) Work out what I need and not what would be nice to have &
b) Read more on networking.

Thanks again,

G

 
Upvote 0 Downvote
M

molletts

Distinguished
Jun 16, 2009
475
4
19,165
A quick and dirty way of doing what Bill001g said, if (and only if) you can configure AP(2) to only provide DHCP services to wireless clients, would be to reduce the DHCP scope of the main router a bit (either reduce the size of the address pool or add a block of exclusions) then set AP(2) to offer DHCP using the excluded addresses as its address pool and giving out the different default gateway.

For example:

Router:
Subnet: 192.168.1.0/24
DHCP pool: 192.168.1.32 - 192.168.1.224
Default GW: DSL router's address

AP(2):
Subnet: 192.168.1.0/24
DHCP pool: 192.168.1.225 - 192.168.1.249
Default GW: 4G router's address

This will keep all the clients on the same subnet, so they can see each other, but give them different gateway addresses.

If you can't configure AP(2) to only offer DHCP over wireless, don't try this because it'll just mess up your existing scope.
 
Upvote 1 Downvote
G

Grubby66

Commendable
Aug 30, 2016
4
0
1,510
Yes - it's the configuring of AP(2) to only offer DHCP over wireless. It's 'very' consumer grade and can't do that. Perhaps I should just thank my lucky stars that I can now get 4G after 12 years of 300K over my landline! :)
 
Upvote 0 Downvote
M

molletts

Distinguished
Jun 16, 2009
475
4
19,165

Which model of Netgear switch are you using? Some of their smart switches do offer DHCP filtering (and even static routing) which would allow you to do this without having to disable wired DHCP on AP(2). You could simply enable DHCP filtering on the port the access point is connected to.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom