Slave router facing IP issues

[Hasan11]

I have a Netgear router down stairs that has 4 LAN ports and 1 WAN port. My ISP uses the WAN port to connect his wire in it.
I wanted to extend it's range so I connected a DLink router upstairs with an ethernet wire, the DLink has LAN ports and a DSL port, So, Initially, when I connected the two, not surprisingly, the master router treated the dlink as a wired device and that in turn allowed me to connect only one device at a time to the dlink.
So, I made a few changes in the configuration for both these devices.
1- I changed the security type of the dlink to make it the same as the master (WEP passphrase) and made the channels the same for both (5)
2- Changed the default gateway of the DLink from 192.168.0.1 to an IP address in the master's pool range but far away from what it assigns to devices usually. By that I mean, the master assigns IPs like 10.0.0.2 and so on, and I gave the slave an IP address of 10.0.0.114
3- Turned on DHCP server on the slave too, and allowed it to assign IPs in the range 10.0.0.115 to 10.0.0.254 whereas the master's range is 10.0.0.2 to 10.0.0.254.

After making these changes, both work, but, for some time. What happens after a few hours is that both the routers stop working except on some devices connected to either router. I checked the router configuration to check what IP addresses do devices have, the devices connected to the master had addresses close to 10.0.0.2 and the slave (which itself and its connected devices are shown as WIRED devices on the master router's config) has the IP addresses in a similar range (NOT IN .115+ which is what I allowed to the slave's range). The slave router's IP address remains static (10.0.0.114) all the time listed as a wired device in the master's configuration.

I am not sure what happens after sometime, but I feel it's an issue of IP addresses getting mixed up, could somebody help?

 

[Ralston18]

Duplicate IPs most likely.

As I understand your post the master router's available DHCP IP address range includes the DHCP IP address allocated to the slave router.

You need to turn off DHCP on the slave router.

Only one router (Master) should be assigning DHCP IP addresses.

And the slave router will actually be and should be configured to be an Access Point.

Limit the DHCP IP address range to the number of devices (wired and wireless) you truly expect to support. Plus a couple of extra if you have guest users.

Too many users, even with all the available IP addresses will slow network performance to a crawl - even when correctly configured.

Check both router's documentation and configure the master router Netgear to assign DHCP IP addresses. Then configure the upstairs D-Link as an Access Point per its' respective Guide/Manual

Plan it all out using a diagram of your own. And add in the IP addresses as applicable. Many examples on line.

Just google for "Access Point diagrams images".

Then narrow to include NetGear and D-Link.

Also look for "How to set up an access point". More to be found.

End result should be something like the following line diagram:

ISP --->DSL modem ----> [WAN] Netgear [LAN] -----Ethernet cable ----->[LAN] D-Link [LANs]----- Ethernet cables to other wired devices-->