@Riley_S 

RE550 V1

I have the same problem and my device (IoT device) cannot set a static IP-address. Therefore I would need to reserve the adress using DHCP of router. Unfortunately thats not possible, because of the wrong MAC-address passthrough by the extender. Is there a possibility to rollout a firmware update in the near future, which fixes this problem and allows Proxy Mode at least? 

I must say, I am kind of frustrated. I don't want to buy another range extender, just because this one doesn't function properly. 

  @Riley_S @Alphabeet 

As TP-Link tech support stated to me the RE550 only operates in "Universal Mode" previous community post and all client mac addresses are converted to a single mac address when sent to the connected router.  This is very unfortunate (that the RE550 does not support proxy) as many routers are not compatible with this Universal mode and will keep reseting the wifi connection between the client device and the router due to mac address conflicts.

If there is a way to change the RE550 to a proxy configuration, someone from TP Link should test and post directions specifically for the RE550.  After many hours of troubleshooting and working with the RE550 (I believe it had a "blue") UI, I had no success and had to get another router essentially leaving the RE550 as unusable. 

Unfortunately, I never found a proxy mode for this extender.

Thank you.

  @asbstn @Riley_S 

It is exactly as stated out. My RE550 has the newest firmware version available for hardware V1.

So therefore it is an issue of the RE550 not my setup. That's why I was asking if TP-Link has the possibility to release a firmware update, which would fix this issue. It cannot be real, that I pay more than 50 € for a range extender, and it doesn't even function properly. I hope a future firmware update, which might be released ASAP can fix this.

  @asbstn 

In my case I had got the thing working - except like you notice I started to hit issue where the IP address would be that of the repeater. Not cool.

So I have a TP-Link Archer 2800 v1 connected to FTTP.

This dishes an IP to the RE550. I had hoped that being the same brand it would "just work". Hmmh.

Finally I have a NetGear wpt2000 that received signal from the RE550 and serves another network.

Today I hit similar issue to you - I am wondering if part of the issue might be TPLink might have messed up the Mac on the device?

NETWORK MAC

2.4GHz xx-xx-xx-xx-xx-zE

5GHz    xx-xx-xx-xx-xx-zF

Wired   xx-xx-xx-xx-xx-zE

So my wired connections's Mac is apparently the same as the 2.4GHz.

The 5G is as 2.4G but incr the last hex digit.

Surely this is wrong - two ports with same mac? How on earth can another device supply a fixed IP based on Mac filtering?

Anyhow - this unit is likely going back to Amazon as even with its latest firmware the unit isnt fit for purpose (and my Archer shows TPLink happily abandons devices without support / firmware update)

Hello community, I have the same problem on my RE305. I have disabled DHCP and upgraded to the latest firmware, but I am unable to solve the problem. Is there a way to solve this on the RE305? It is causing multiple problems in my network and is starting to be very frustrating.

Same story here. I have it up and working and seems to work great as a repeater to my yard where I have a remote camera and solar charge center set up but my monitoring tools and camera softare are constantly having issues due to the MAC address being the same for all of the connected devices. I've tried static IP's as mentioned but still the same outcome. Hoping there is some firmware update that will address this. 

Edit: forgot to mention, I'm not on an RE, I'm using a WA1201 in repeater mode, but the issue is the same. 

  @Riley_S I bought my RE505X only very recently, unfortunately I have the same issue. Clients behind my RE505X cannot be assigned a static IP address because the MAC address is the same for them.

An update will be needed for the RE505X or I'll have to return it and find something better

  @asbstn 

Same issue with CPE-710. I made a link between to buildings using two CPE-710 antennas, one in access point mode and the other in client mode.  The mac address of CPE-710 client is assigned to all devices which are connected on this antenna.