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Using WR840N as secondary router, should DHCP ON? or OFF?

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Using WR840N as secondary router, should DHCP ON? or OFF?

This thread has been locked for further replies. You can start a new thread to share your ideas or ask questions.

jimjoe

2022-03-29 01:12:45

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Using WR840N as secondary router, should DHCP ON? or OFF?

2022-03-29 01:12:45

Model: TL-WR840N

Hardware Version:

Firmware Version:

Should DHCP ON? or OFF?

I am using WR840N as secondary router to my main modem/router(Primary) from ISP.

I always thought that only primary router should have DHCP ENABLED, and any secondary router DHCP should be DISABLED.

WR840N operation mode is set to "wireless router", and DHCP by default is ENABLED on WR840N.

Yet I can get internet from WR840N and no IP conflicts.

How is this possible?

Maybe Operation Mode set to "wireless router" require DHCP ENABLED?

Another question:

I thought cable(Cat5) from primary router should fit into one of four LAN slots (thus leaving 3 LAN slots only).

But cable is connected into WAN slot, and I can still get internet via cable(to PC) and wireless.

How is this possible?

So I have two settings (DHCP and WAN) that are technically not allowed (can cause IP conflict, etc..not able to get internet), yet ia hev no problem getting internet.

Any explanations?

3 Reply

terziyski

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2022-03-29 01:51:23 - last edited 2022-03-29 01:54:28

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Re:Using WR840N as secondary router, should DHCP ON? or OFF?

2022-03-29 01:51:23 - last edited 2022-03-29 01:54:28

@jimjoe

This behavior is quite logical:

You have a double NAT in your network with this configuration.

Once from your ISP modem/router and then again from WR840 (which is in 'wireless router' mode). When in 'wireless router' mode WR840N has its DHCP ON.

If your WR840N has 'access point' mode use that mode instead and then the DHCP should be OFF since only your ISP modem/router DHCP will be enough.

See here an example of configuring a wireless router in AP mode.

There are two cases:

1. Device has dedicated AP mode in this case you're using second router WAN port.

2. Device doesn't have dedicated AP mode - you were referring this scenario. In this case you're using second router LAN port.

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jimjoe

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2022-03-29 02:09:26

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Re:Using WR840N as secondary router, should DHCP ON? or OFF?

2022-03-29 02:09:26

@terziyski

k. I get somewhat what you are saying. (only cus I don;t have network knowledge to understand NAT, etc.. but I get general meaning)

So is WR840N assigning different IP address than primary router(ISP)? I mean (as I understand) DHCP is assigning IP addresses, so in my network Primary and secondary routers are both assigning IP addresses? Shouldn't I have to "reserve" certain IP addresses for primary and secondary routers?

BUT shouldn't this cause IP conflicts(or some problems?) that will NO internet? But I am getting internet(LAN dn wireless) just find connecting to WR840N.

Forgive me for not using certain terms correctly, and explaining what I understand. This networking is FUN to learn.

terziyski

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2022-03-29 03:02:04 - last edited 2022-03-29 12:18:58

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Re:Using WR840N as secondary router, should DHCP ON? or OFF?

2022-03-29 03:02:04 - last edited 2022-03-29 12:18:58

@jimjoe

Yes, both of your routers DHCP servers are assigning an IP addresses in their LAN subnets.

For example your ISP router's DHCP may assign IP addresses in 192.168.0.1-192.168.0.100 space (just an example).

While your WR840N's DHCP may assigns IP addresses in 192.168.1.1-192.168.1.100 space (just an example).

As you can see there is no conflict between these two subnets cause they differ by its 3-rd octet ('0' or '1' in this example).

That the reason you have an Internet connection and everything works.

While this is working it's better to have all of your devices (whether they are connected to one or the other device) in only one subnet (your ISP router subnet 192.168.0.X for example) - that's the purpose of an AP mode from my previous post - to extend your local network without complicating it.

This way you'll avoid complication in accessing your local devices, gaming issues, complicated network troubleshooting, etc.

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Using WR840N as secondary router, should DHCP ON? or OFF?

Using WR840N as secondary router, should DHCP ON? or OFF?

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