My understanding of that is, when you configure your LAN, you should provide a DHCP range that is smaller than your network. Then make an IP reservation for IP addresses from outside of your DHCP range.

Otherwise the DHCP will overlap with your static assigment.

There seems to be confusion here between a 'static' IP and a 'reserved' IP.

A static IP is where the IP is configured directly on the device and in that case, yes, it must be outside the DHCP range , to avoid the router giving out the same IP to another device from its DHCP pool.

A reserved IP is where the router assigns the IP via DHCP but always assigns that IP to the device. Obviously, in this case the IP must be inside the DHCP range since it is being assigned by DHCP!

Hope that helps

  @Tedd404 

Yes, I have worked out that I hadn't assigned the VLAN to any particular port. Total noob moment of realisation, since I had even planned out which ports would be which VLAN, and I had just had an oversight when configuring the networks!

FWIW, DHCP reservations do work if the IP is assigned outside the DHCP range. For example, I have 2 dumb switches in the mix, and I set each to have an IP of .3 and .4 on the subnet, with the DHCP range set to .20 - .255, and this was successful.

Appreciate the help 👍

Hello!

Thanks to everybody constructively contributing to this thread.

For putting focus back to the initial topic I'd like to repeat and clear up, what I already had written.

Please have a look at my network configuration (see attached screenshot).
All configured DHCP reservations are IP addresses with the last part being lower than 201 (start of the DHCP range) and larger than 1 (address of router).
End of lease time has no effect on the assigned IP addresses - the previous assigned IP address is being kept.

The problem is:
When the router assigns the IP address, it ignores the DHCP reservation and assigns the client device any IP address from the configured DHCP range instead.
This happens on client device reconnect - either after restart of the client device, or after reboot of the router.
So, the problem is not solved by rebooting the router, nor by rebooting the client device - it is the direct opposite.

As I found out in this article, this behavior should have been resolved since controller version 5.0.29:

https://www.tp-link.com/us/support/faq/3200/

With "client device" I mean any device connected to the ER7212PC router - end devices as well as EAPs (EAP650-Outdoor, EAP650-Wall, EAP655-Wall), connected via ethernet cable as well as via Wifi (provided by the EAPs).

The only way to assign the reserved (not static!) IP address to the configured client device using the Omada controller web interface is:
- Click on the client.

- Click on 'Config'.

- 'Use Fixed IP Address' is already active, 'IP Address' is correct as already configured in the DHCP reservations.

- Click on 'Apply'.

> After a while the router assigns the right - I mean reserved - IP address to the client device.

So, after all:
How can I "motivate" the ER7212PC to assign the reserved IP addresses to the client devices as configured in the DHCP reservations, when a client device is being (re-)connected?

Thank you very much for any useful hint.

Kind regards,
Gerald

  @gerba I'm experiencing the same issue with a TL-SX3206HPP switch running under an OC300 controller and ER8411 router.  In this instance, there isn't a config setting for the switch to set a fixed IP address; the only way that I see that a 'static' or fixed IP address can be set is to use a DHCP Reservation.  But, even after setting the reservation for an IP address outside of the DHCP pool and rebooting the switch, router, controller, and finally, sacrificing a chicken,...etc, the switch is still being assigned an IP address within the DHCP pool.  As previously mentioned, this is a bug that had been previously fixed but looks to have been reintroduced.

Update:
The TP-Link Technical Support due to a correlation issue with 'IPSec Failover' recommended to reset the ER7212PC and "reconfig the ... network settings in the initial state, but do not enable IPSec Failover, not even click on it."

I followed that advice and now even after rebooting the ER7212PC the reserved addresses are assigned and kept properly.

I just noticed, that after applying a new DHCP reservation, the device does not get the reserved address, until it reconnects, although the DHCP lease time is set to 15 min.
Why?

Kind regards,
Gerald