GL.iNet Flint 2 router review – Part 2: WiFi 6, 2.5GbE, WireGuard performance

In the first part of the review of the GL.iNet GL-MT6000 “Flint 2” WiFi 6 router, I had a look at the package content and the hardware design with a teardown of the router, and quickly tried it out. I’ve now had more time to play with the router focusing the review on WiFi 6 and 2.5GbE performance, and checking whether of 900 Mbps Wireguard VPN claim had any truth to it.

The router also supports the Tor network to anonymously browse the web, Adguard Home to get rid of unwanted ads, and Repeater mode among other features. Those all work with the Fliont 2 router, but I won’t cover those in detail here, and invite you to check out the GL.iNet Brume 2 security gateway review for Tor and Adguard Home and the GL.iNet Beryl AX review for the repeater mode test.

Connecting wired and wireless clients

The Flint 2 router is pretty much plug-and-play, and after I set the timezone, and changed the name and password for the 2.4GHz and 5GHz SSID, I had no issue connecting multiple wired and wireless clients to the router.

The GL.iNet Admin Panel also lets you see how much traffic goes through each client and allows you to block some clients if needed. Note that network acceleration is enabled by default for the best performance, so if you set client speed limits, they may not work as expected.

Flint 2’s WiFi 6 performance test

Now that we know the basic features are working as expected, it’s time to test the performance. We’ll start with WiFi by running a SpeedTest using an Android smartphone connected with a 433 Mbps link and a 300Mbps 3BB fiber to the home broadband internet plan.

All good. But the Flint 2 is a WiFi 6 AX6000 router that can support up to 4,804 Mbps at 5 GHz with multiple clients. I won’t test the maximum speed with multiple clients, but I will use the Khadas Mind mini PC running Ubuntu 22.04 since it delivered the fastest WiFi 6 connection in our reviews with 1.4 Gbps upload and 991 Mbps download speeds when connected to a Xiaomi Mi AX6000 router.

Let’s do that again with iperf3 with the Khadas Mind connected to the 5GHz SSID from the Flint 2 router using UP Xtreme i11 mini PC on the other side.

• Upload:

• Download:

943 Mbps and 890 Mbps are pretty good results, although somewhat lower than with the Xiaomi router.

That’s because the link speed was set to 1200 Mbps, while the Khadas Mind had a 2400 Mbps link speed with the Xiaomi Mi AX6000 router. This is obviously device-dependent, as my phone is connected with a 433 Mbps link to the same router.

I also tested 2.4 GHz WiFi for reference:

The link speed was 270 Mbps at 2.4 GHz. The specs claim up to 1,148 Mbps @ 2.4 GHz, but that’s for multiple devices.

Finally, I had a look at the range of the routers. Both the Flint 2 and the Xiaomi Mi AX6000 were on the same table at around one meter from each other.

The signal strengths are similar.  The channel graphs at 2.4 GHz look the same, and they are just using different channels, but the GL-MT6000 Flint 2 router has a much narrower graph at 5 GHz since it uses fewer channels. The first two screenshots were taken about 4 meters from the router. The one on the right was taken in a bedroom about 6-7 meters from the router in a different room. All show a  0-1 meter distance from the router, so the distance reported in the app is not that relevant at least when close to the router.

I then walked outside and could use 5 GHz up to about 40 meters from the routers (distance as measured in Google Maps) and 2.4 GHz up to 80 meters. I could not see any obvious difference in range between the GL.iNet and Xiaomi routers.

Ethernet performance on the Flint 2 router

I used an Ubuntu 22.04 laptop with a Realtek RTL8156BG USB 3.0 to 2.5GbE dongle and UP Xtreme i11 mini PC’s 2.5GbE interface to test the performance of the Flint 2 router with 2.5Gbps Ethernet. Note the laptop was connected to the 2.5GbE LAN of the router (192.168.8.0) and the mini PC was in the WAN of the router (192.168.31.0), so routing is also involved here.

• Transfer from the laptop to the mini PC

• Transfer from the mini PC to the laptop

2.35 Gbps in either direction, so no problem here.

I also did a bidirectional/full-duplex transfer:

That’s 2.21 Gbps and 1.99 Gbps in either direction. Still pretty and most people won’t mind, but if you have a really fast internet connection and are seeding a torrent it may matter somewhat…

I also quickly tested the four gigabit Ethernet ports with the same method:

• LAN 2: 940 Mbps / 941 Mbps
• LAN 3: 940 Mbps / 941 Mbps
• LAN 4: 940 Mbps / 941 Mbps
• LAN 5: 940 Mbps / 941 Mbps

No issues there…

WireGuard VPN performance of the Flint 2 router

It’s now time to put the 900 Mbps WireGuard performance claim to the test. For this, I installed a Wireguard VPN server on UP Xtreme i11 mini PC using the wireguard-install script, and copied the client file to the Flint 2 admin panel in the WireGuard Client Section:

The connection was shown as successful in the Admin Panel…

and I could ping the virtual IP from my laptop as well.

I could log in to the UP Xtreme i11 computer over SSH:

So I tested whether the 900 Mbps claim was valid with iperf3:

• Laptop to UP Xtreme i11

• UP Xtreme i11 to Laptop

Well… They didn’t lie here :). We have pretty good VPN performance. Double-checking on the UP Xtreme i11 mini PC, we can see a large amount of data was transferred over the wg0 interface:

Let’s now switch to WireGuard Server mode.

The Admin Panel will generate a configuration automatically for us, and I could start the server.

I also added the UP Xtreme i11 as the first client in the Profiles section.

The Admin Panel will provide a QR Code which will be convenient for the Wireguard Android app for instance, and a config file that looks like this:

So I ran the wireguard-install script again on the UP Xtreme i11 to remove the WireGuard server installation, and installed the WireGuard client instead along with a dependency:

I created the /etc/wireguard/wg0.conf file with the data above except I changed the Endpoint since I enabled DDNS from my ISP through a special service as it won’t even give me a temporary public IP address since my Internet connection is in a VLAN, and I only get a private IP address. That also means the built-in DDNS service provided by GL.iNet can’t work with 3BB internet service provider. So the line looks like this:

But it failed… and no traffic was exchanged:

I could confirm 3BB DDNS service was working fine after I accessed the Admin Panel from the Internet, but WireGuard is using UDP so that might be the reason… I can set the broadband router to forward TCP/UDP data, but there’s no such option on the 3BB DDNS website, so it’s unclear how UDP traffic is handled by the ISP. I might try it again in another house in a few weeks, where I do have a public IP address so the built-in DDNS service should work.

Anyway, I decided to change the config to use a local IP address instead just like I did for the Wireguard Client test:

And it looks better with some received and sent packages:

And the UP Xtreme i11 also shows as a VPN client in the GL.iNet Admin Panel.

But for some reasons, it’s not very stable:

I tried to do the same with the OPPO A98 5G smartphone, and it works much better.

I could confirm the stability with iperf3 with the phone connected through a 433 Mbps link.

But it’s not really exploiting the full performance of the router, so I did one last try in a Ubuntu client with my laptop.

It quickly appeared in the list of VPN clients after I followed the same step as with the UP Xtreme i11 that is shown as offline despite the wg0 still up.

I then shut down the wg0 interface in the UP Xtreme i11 and ran iperf3 from there to 10.0.0.4 accessing my laptop through the WireGuard network.

• UP Xtreme i11 to Laptop

• Laptop to UP Xtreme i11

The performance is excellent, although quite lower than 900 Mbps for the laptop to mini PC transfer. At the time of the test, both devices were connected through Gigabit Ethernet.

Misc features

GL.iNet routers are versatile with plenty of features that would make the review really long, potentially boring to readers, and time-consuming to complete, so it’s not practical to test everything. But I’ll still show the list of features, some of which have already been tested in previous reviews as mentioned in the introduction.

The Applications section offers menus for plug-ins (packages that can installed in the router), dynamic DNS, GoodCloud for remote access, network storage (we’ll test that below), parental control, and services such as ZeroTier and Tailscale.

The Network section allows the user to configure the firewall, multi-WAN, LAN, guest network, DNS, IPv6, NAT, network acceleration, and more…

The System section provides some information about the router, and for example, we can see the GL.iNet Flint 2 runs OpenWrt 23.05 (or more likely a fork although it’s also officially supported) on top of Linux 5.15.139 with the latest firmware. We also get menus for firmware updates, scheduled tasks, time zone configuration, logs for debugging/troubleshooting, security (password, remote access to admin panel, etc…), factory reset, and advanced settings that point to the OpenWrt’s LuCi web interface.

I decided to quickly try Network Storage by connecting our “review” USB hard drive. The Flint 2 has no problems mounting the NTFS, EXT-4, and exFAT partitions, but is not so pleased with the BTRFS partition…

The next step is to enable Samba in the File Services tab.

After I set a shared folder on the EXT-4 partition in the Shared Folders tab.

My Ubuntu 22.04 laptop could see the GL-MT6000 share (twice! not sure why…) and I could log in with the credentials I set in the Admin Panel.

I could then transfer a large file from the router to my laptop at around 31.3 MB/s.

That’s quite slow considering that’s a USB 3.0 port and my drive should support around 95 MB/s. But at least it works.

Conclusion

GL.i.Net Flint 2 (GL-MT6000) is a solid router with two 2.5GbE ports, four gigabit Ethernet, support for WiFi 6, and an Admin Panel with plenty of features that should meet the needs of most users. I would confirm the 2.5GbE and WiFi 6 performance was excellent and verified the 900 Mbps WireGuard VPN claim both in Server and Client modes, although it drops to 834 Mbps in Server mode in one direction.

I did not encounter issues that should not be directly related to the Flint 2 router. Notably, I did have some challenges with my ISP which appears to block UDP traffic (so WireGuard is not an option, now that I think about it the slower OpenVPN might work) and one of the WireGuard VPN clients could not connect reliably to the Flint 2 WireGuard server for unknown reasons (it could only connect for a few seconds, and then disconnected). The only real disappointment was the slow transfer speed (a little over 30MB/s) for SAMBA using a USB 3.0 drive and gigabit Ethernet.

I’d like to thank GL.iNet for sending the GL-MT6000 “Flint 2” AX6000 router for review. It can be purchased for $159 with free shipping on the company’s store or on Amazon.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.

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