@Kevin_Z I have this same router, Archer C7 v5, and hairpinning (NAT loopback) is definitely not working. I've even tried to disable NAT Boost, since one online discussion of this said that worked, but it doesn't work for me. I have the latest firmware update: 1.0.11 Build 20190726 rel.57101(4555)

Any other advice?

Edit: I've contacted TP-Link support to ask about this, but I don't know what to expect so I would still appreciate any replies.

UPDATE: Everything is actually working fine (sort of), this was a case of minor misconfiguration.

I was trying to access an FTP server hosted by a Raspberry Pi on my network. The issue was that the router had its own FTP server for the USB storate, and for local connections it was apparently taking priority:

(screenshot is from the emulator, but settings are similar to my own)

As soon as I disabled the second line "FTP", everything started working as it should.

In my opinion, this is unwanted behavior. In the case of NAT loopback, connections should be treated as though they came from the WAN and be routed according to those rules. In this case, the router's FTP server is only available from the LAN, so I don't expect NAT loopback to reach it. I expect to reach it only by explicitly using the router's local IP, which is 192.168.1.3 in the screenshot above.

I realize this is probably impossible to fix with a firmware update - even if it can be, it would be an unexpected change for many users, and that's not normally welcome. However, I would like it if this is brought to the attention of TP-Link engineers, for the sake of future products.

Does the C7 v2 have loopback? I'm having problems accessing my internal server using the public IP and I'm guessing that's the issue. No issues accessing from the public internet, so port forwarding is working as intended.