Hi @Solla-topee

Last year I posted about the DHCP server issues with various TP-Link Range Extenders that myself and others were having (setting a static IP didn't disable the range extender's DHCP server.)  I'm glad to say that the newer firmwares released since have fixed the issue (I have been away from home due to family emergency, so couldn't post again until now.)  Thank you for your help on the DHCP server issue; however,  there's also another fairly serious issue with the newer firmwares that I posted about here and here that has not yet been fixed-

Turning on RE205 (or rebooting) breaks LAN with network switches (for 15mins)

Description of problem:

When running recent firmware (1.1.0 and above) on my UK RE205 V2, in Access Point mode, with a Static IP, when starting up (afresh or after a reboot) the RE205 appears to be sending packets to the RE205's Ethernet port with that have the source IP address set to Router's IP address.

I know this is happening because of a message I see in the Router's logs just before devices get disconnected-

Feb  5 20:49:09 Router user.warn kernel: eth3: received packet with  own address as source address

Understandably, when this happens, I think it's confusing the network switches and/or my router LAN and causes the LAN to "split" and many devices on the LAN to be kicked off the Internet (and unable to access the Router and most other devices on the LAN.)

The problem resolves itself after 15 minutes (which is presumably the ARP cache timeout.)

This issue only triggers when the RE205 is booting up and when running firmware versions 1.1.0 or newer.  Firmwares based on 1.0.1 work fine.

Home Router:

Netgear DGND3700v1 (running custom firmware.) 

Wired LAN configuration:

RE205 --- Network Switch 1 --- Network Switch 2 --- Router --- Internet
                 ⏐                    ⏐                ⏐
                 ⏐                    ⏐                ⏐
             Computer 1           Computer 2      Computer 3

Device with problem: 

TP-Link RE205 V2 (UK).

Firmware versions that work:

1.0.1 Build 20181123 Rel. 56934

Firmware versions that don't work:

1.1.0 Build 20190929 Rel. 78177

1.1.2 Build 20201202 Rel. 39451