Pi Hole slowing down internet speed

Why does Pi hole slow down my internet Speed, i have 1gb Fiber line, Speed test Before enabling Pi Hole between 800mbs and 900mbs, after enabling Pi Hole, speed drops to under 150mbps.
Also the wifi becomes very unstable?

debug token - j4ate5xocn

Pi-hole has no effect on your internet speed. None of the data traffic from a client goes through Pi-hole; that traffic is solely between the client and the router. Only the very low bandwidth DNS traffic goes to the Pi-hole. Pi-hole also has zero impact on the WiFi stability on your network. The Pi-hole host joins the network just like any other client.

A possible cause of what you see with speedtest - the server being used for the test is not the optimal server and the test is reporting an inaccurate assessment of your internet speed.

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how is your pi-hole connected to the router?

I've connected my pi-hole to the router using Ethernet instead of using the wireless network on the raspberry

Shouldn't matter one way or the other. Could be connected with a DB-9 serial interface and you'd very likely never know.

true, but we don't know if wireless is flaky or unstable.

Again, doesn't matter. DNS is the only thing going to the Pi-hole, it could be off for every other second and it's not going to slow down WAN speeds.

Even if the WiFi were flaky or unstable for some reason, (1) that would not be caused by Pi-hole and (2) the OP appears to be testing speed from a client connected via ethernet based on the speeds recorded.

I am connected directly to the router useing a lan Cable.

The Answers does not give me any indication of where to look to fix the problem, you are responding very Generic.
Have you seen my Debug Token

I am not a linux person but i know enough on routing, and once i put the Pi-hole IP as a dns on the router the internet speed drops like crazy.

I have even tried not adding any block list to pi-hole and it does the same thing as drop the wifi speed.
The minute i remove the Pi-Hole DNS IP on the router the speed goes back to normal?

Please can you assist in identifying the where the problem lies.

I have a standard setup, Fiber, to my Mikrotik Router and Rasberry Pi 4 - 4gb thats is all i have.
Standard Mikrotik Router Firewall and thats it.

Regards

Regards

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I also doubt that any DNS server could cause this, unless you try to download each byte from a different host and require dns resolution...

Check the load on the Pi when downloading does it goe up? Do the DNS query go up when downloading?
doubt that

Your debug log shows Pi-hole is not used/usable as a DNS server in your configuration, though basic IPv4 network connectivity seems ok:

*** [ DIAGNOSING ]: Networking
[✓] IPv4 address(es) bound to the eth0 interface:
   192.168.88.222/24 matches the IP found in /etc/pihole/setupVars.conf

[i] Default IPv4 gateway: 192.168.88.1
[✓] Gateway responded.

*** [ DIAGNOSING ]: Name resolution (IPv4) using a random blocked domain and a known ad-serving domain
[✗] Failed to resolve  via localhost (127.0.0.1)
[✗] Failed to resolve  via Pi-hole (192.168.88.222)
[✓] doubleclick.com is 172.217.170.14 via a remote, public DNS server (8.8.8.8)

This would commonly hint at a firewall on your RPi 4, blocking access.
Please check that ports required by Pi-hole are accessible.

The only way I could fathom how that would impact a speed test:
Your speed test tries to spread the load over a bunch of servers to assure your download bandwith can be easily maxed out, and its accessing those servers by name. Rather than reporting a DNS failure for e.g. five out of six servers, drawing the sixth from its cache, it then just reports a lower doonwload speed.

I'd recommend sorting your network/firewall issues before repeating your speedtest.

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