R7800 with OpenWrt: different IP adresses and speed issues


I've just flashed my R7800 with the latest hynman build using TFTP.
Everything works fine. I have internet but there are some strange "issues" I don't really understand.

I've just done a speedtest @ speedtest.net and only got 100mbit download.
My public IP was 80.192.xxx.x.

I've switched my LAN cable from the OpenWrt router to my modem (bridge mode).

There I got >300mbit full speed but also a very different public IP Address: 212.45.xx.xxx

Shouldn't I have the exact same IP with both devices because the router is connected to the modem?

Also how can I get my R7800 to run at full speed?

Thanks for your help :slight_smile:

you should, the question is what you were connect to ...


well, my modem has 4 ports and it is setup as bridge mode.

internet -> modem -> router -> PC ... I always get the IP 80.192.xxx.x.

internet -> modem -> PC ... I always get the IP 212.45.xx.xxx

for me this is kinda strange. how can it be that there are different IP addresses?
as said I've just flashed my R7800 with the latest hnyman built because of that issue.

before I also got >300mbit with my router. What can it be and how can I find out !?

is the 80 the public IP ?

how are you connecting to the 7800 ? wired or wireless ?
wireless is disabled by default in vanilla openwrt (can't say if it is on hynmans builds, never used them), are you sure you're connected to the right device ?

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Everything is connected via LAN cable. WLAN is completely turned off.

The IP of my LAN network with it's devices connected to the router is 192.168.x.x.

So the LAN network is working but I don't understand why my IP changes on the internet after switching the LAN cable from the router to the modem.

As you can see after switching my LAN cable from the router to the modem the websites displays a complete different IP Address and I am wondering if that is normal.

Also I don't understand why I only get 100mbit with the router but > 300mbit with the modem.

did you try to exchange the 2 Lan cables to the modem ports?

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Yes I did. I justed the same port, tried different ports. I get another public IP address.

Try cloning the MAC from the PC to the wan port of the 7800.

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Thank you I will try to do that.

Regarding the speed I really don't know why it's capped at 100mbit with the router.

Is there a specific setting to check?

The DHCP from your provider is basing the IP address it hands out on the MAC address of the device connected to your cable modem. Many cable modem providers work this way, where their DHCP server keeps a semi-static registry of MAC address to IP address. This dates all the way back to the pre-router days when the method of hooking up more than one computer to your cable modem was to put a hub on the cable modem and direct-connect multiple computers to it.

The reason the IP addresses are vastly different is due to IP exhaustion and the fact that ISPs are getting doled out dribs and drabs of IP blocks from all over that are getting reclaimed from other users that didn't need the size of block they registered in the past. Or large national providers that are moving blocks of numbers over from one region to another.

If you set your router's MAC to the PC's MAC, I suspect you'd get 212.45.x.y handed out to your router.

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I have two suspects

  1. Not enough horsepower. This is the less likely of my ideas. To check you can ssh into the router and run htop on it when you are doing a speed test. Check to see if one of the cores spikes to 100%
    One would think it would have the horsepower for >100mbit, but it's one thing to look at. You can also just turn on software flow offloading and see if that affects the speed.
  2. More likely is a failure to negotiate a gigabit ethernet connection. That 100mbit seems too handy to be a coincidence. You may find that a combination of the network cable/adapters between the router and the modem are causing the link not to negotiate at one gigabit. This is less common today than it used to be, but even today a marginal cable can often work in one place but not another, or it turns out that the adapter in a cable modem just fundamentally doesn't like the ethernet in a particular router. Look at the cable modem's ethernet lights - usually there is a way to tell if it's gigabit vs 100mbit.
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"Cable" usually means plain ethernet+dhcp (so no very CPU intensive PPPoE required), under these conditions the r7800 should be able to do ~600-650 MBit/s (I wouldn't call it a safe bet beyond 450-500 MBit/s though, as you want more of a margin, but you will get roughly those figures without needing to resort to software flow-offloading in speedtests; I have been using my virtually identical nbg6817 on a 400/200 MBit/s fibre connection (no PPPoE needed, without SQM, without software flow-offloading)).

While 111 MBit/s is suspiciously close to 100 MBit/s, which might hint at issues with the auto-negotiation (between 100 MBit/s and 1000 MBit/s) for your modem- and router, it above that figure, so… Well, ethtool (or even just dmesg) should answer this (easy-) question. Having a look at htop under load is certainly also worth looking at.


Thanks for helping me.

Well, it can't be the router nor the cables. I've had fullspeed all the time. The issue just occurred some days ago and because of that I've flashed the router with the latest hynman build.

What I did now was changing the MAC Address of my router to the same as my network device on my PC. I actually got the exact same IP now but still I got only 100mbit. So the issue has to be somewhere at the settings itself.

I just wanted to install ethtool but after I've installed AdGuardHome as desribed on the openwrt website, I am not able to use opkg update anymore. my router got no connection to do it but my internet connection/browsing works just fine.

...guess I have to re flash again...

logread -f while unplugging/ replugging the wan cable might already tell (part of) a story - but you really want opkg to work anyways.

So I've reflashed my router and re-installed AdGuard Home using this tutorial:

Again no connection to the internet from the router. Do I need to change some settings in AGH?

I've uninstalled AGH now my router has connection again.

so with "ethtool eth0.2" i got the following info:

Settings for eth0.2:
        Supported ports: [ MII ]
        Supported link modes:   1000baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  1000baseT/Full
        Link partner advertised pause frame use: No
        Link partner advertised auto-negotiation: No
        Link partner advertised FEC modes: Not reported
        Speed: 1000Mb/s
        Duplex: Full
        Auto-negotiation: on
        Port: MII
        PHYAD: 0
        Transceiver: internal
        Link detected: yes

I really don't know where else to look at and figure out why I only get 100mbit with when going through the router.

Is there anything else I can do to fix that problem?

I've looked into many threads here regarding speed issues with r7800 but nothing came up that would help me.


Okay I've just flashed the latest original openwrt firmware and get full 300mbit.

seems the hnyman build didn't work for me. there has to be something in there that caps my router at 100mbit.

Sounds strange as my build has no special tweaks regarding network or speeds.

Btw. what do you mean by "latest original openwrt"? 22.03.3 or master snapshot?

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You got me scared for a while, as I tested my r22387-47de2c6862 with the Ookla speedtest, and got only 112 Mbit/s download, while I am supposed to have 200/200 from ISP.

Well, then I tested with the (more modern) waveform bufferbloat test site and got repeatedly the proper 195/185 (without SQM). And a bit lower speeds with the SQM limits active, naturally

Then I tested with Ookla again, and the results varied a lot by changing their server from the default one. Download speeds varied between 110-125-160-220 even with servers in the local Helsinki area. Makes me suspicious about Ookla's reliability with >100 Mbit/s speeds with browser based tests.

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https://github.com/openwrt/openwrt/pull/12258 might be an explanation.

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