Since the network is already configured, I'll use text descriptions instead of images for some pages—it would be too troublesome to reset the network just for writing this blog post.
Preface
My TP-Link XDR-5480 has a peculiar design choice: when you disable the router’s DHCP service, all its ports (including the SPF-converted port) become LAN ports. This makes it impossible to use the modem in bridge mode + router PPPoE dial-up for internet access. Additionally, your LAN port IPs can no longer be manually assigned and will instead be obtained from the upstream router (i.e., the modem).
Older TP-Link routers didn’t have this issue—you could freely disable DHCP without affecting the WAN port. Perhaps the product manager for newer TP-Link models thought this would “waste” a WAN port, especially since all newer routers support WAN/LAN port mixing, which inadvertently exposed this problem.
With the recent release of the M4 Mac mini—smaller in size and more energy-efficient—the internet has been swept by the “Mac mini as a soft router + Mac Surge managing the home network” trend. My current network setup has been stable for over a year without any tinkering, but the itch to experiment returned. Then it hit me: my Mac Studio is always running anyway, so why not use it as a soft router like the mini? Plus, the hype around Surge (hereafter referring to Mac Surge) taking over DHCP for seamless whole-house proxy access and “elegant” real-time monitoring of device connections got to me. Embracing the mantra “elegance never goes out of style,” I started brainstorming how to solve this TP-Link issue.
After scouring the web, I found posts like:
And:
Current Situation
Note: Before proceeding, back up your TP-Link (here referring to my XDR-5480 model) router settings to avoid losing configurations if you make a mistake and can’t access the router. Simply export the settings as shown below. Note that the exported config won’t include port or network settings—a thoughtful design by TP-Link’s product team to prevent importing faulty configurations after a reset. Kudos to them!
Network Topology Diagram:
Goal
Without changing the current connection method or subnet of any device (to avoid complaints), use Mac Studio’s Surge as the gateway to manage DHCP services.
Challenges
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After disabling DHCP on the TP-Link, a pop-up warns that all ports (including the SPF port) will become LAN ports, making it impossible to customize port addresses.
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Disabling DHCP on the TP-Link also triggers a notification that all LAN port IPs will be obtained from the upstream router (the modem). While logical for a pure AP, this means Surge can still detect the modem’s DHCP service.
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If Mac Surge acts as the gateway, it will start its own DHCP service and requires no other DHCP services on the network to avoid conflicts and disconnections.
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Combining points 2 and 3: You’d need to disable DHCP on both the modem and the router. But! Without pre-configuring IP-MAC binding on the modem/router, you’d lose WiFi access to both and be forced to reset them (don’t ask how I know). Thus, the modem’s DHCP cannot be disabled.
Solution
Given the above goals and challenges, “Friends, take notes—here’s my deployment plan”:
Step 1: Power Off the Modem
Technically, just disconnecting the modem from the TP-Link suffices. I suggest powering it off to prevent accidentally connecting to the modem’s WiFi. If you’ve forgotten the modem’s WiFi network, simply disconnecting the modem from the TP-Link is enough.
Let’s not configure the optical modem first to prevent its DHCP service from being detected by Surge, which would otherwise prevent Surge from enabling its own DHCP service. Additionally, since the connection between the optical modem and the TP-Link router has already been disabled, when we proceed to turn off the TP-Link’s DHCP service in the next step, the TP-Link won’t automatically detect the DHCP service of the upstream router and change its own LAN port IP anymore.
Step 2: Disable the Router’s DHCP Service
Simply turn it off in the settings. Here, we select “Disable.” After the setup is successful, we’ll change it back to “Auto” later. The reason for switching to “Auto” is for network robustness, which I’ll explain further on.
Step 3: Enable Surge DHCP
This step can be accessed from either the “Overview” or “Devices” tab in Surge:
It will prompt you that Surge will change your Mac’s IP address to manual and fixed. In my case, it’s 192.168.5.100. There are plenty of tutorials online for this, and since you’ve made it this far, you likely know how to set it up, so I won’t elaborate here.
One thing to note is that it will display the router’s address as 192.168.5.1, with the address pool ranging from 192.168.5.100 to 192.168.5.200. I expanded the address pool to 192.168.5.2 to 192.168.5.254 for a broader range.
Step 4: Find the New Router Address
After setting up Surge, if you try to access the router at 192.168.5.1, you’ll find it’s no longer reachable! Don’t panic—because your Mac Studio is now the DHCP server, it will “somehow” assign a new IP address to your TP-Link router (why this happens, I have no idea). Click on “Devices,” look for the one labeled “Hostname Unsuitable for Printing” (it might not be exactly this), and access it via the address bar. You’ll see the familiar router interface again! In my case, the new router IP address is 192.168.5.114.
Step 5: Modify the Router’s LAN Port and Enable PPPoE
At this point, you won’t have internet access because your optical modem isn’t even powered on! Now you can power on the optical modem, wait a few minutes, and you’ll still find that clicking Wan 口已经断开连接 in the router settings does nothing.
But don’t give up! Think about it: isn’t your Studio’s role now similar to when you were tinkering with a soft router? Back then, the optical modem handled the PPPoE dial-up, while the soft router was plugged into the main router or optical modem and managed the DHCP service. Now, my friend, you’ve moved the dial-up device to the router, and your Studio is connected to the main router, effectively turning your Studio into a soft router that handles the DHCP service itself.
The key step here is to manually set the TP-Link’s LAN port IP address to 192.168.5.1 in the settings (otherwise, there won’t be any device on the network with the 192.168.5.1 IP address)!
After manually setting the LAN port IP (even though it’s called a LAN port, it’s connected to the optical modem and can handle PPPoE dial-up!), go back to the internet settings and click “Connect.” You might need to click it 4 or 5 times because the first dial-up attempt can take a while, but it will eventually succeed.
Step 6: Final Steps
At this point, your setup is complete. Now, you need to right-click on connected devices, select “Set Surge as their gateway,” and then reconnect the devices to the network:
You can also enable “Set Surge as the default gateway for new devices”:
Now, all your devices will treat Surge as the gateway, allowing you to monitor their real-time traffic.
Remember how I mentioned in Step 2 that we disabled the TP-Link’s DHCP service? Now you can go back to the TP-Link and change the DHCP service to “Auto.” This is a fail-safe: if Surge’s DHCP service crashes or your Mac fails, you and your household devices can still access the internet, and you, my friend, won’t get yelled at! This is because the TP-Link’s “Auto” setting will detect the LAN’s DHCP service—if none exists, it will enable its own DHCP; if one exists, it will disable it:
Note: If you click “Disable” and save, your router’s address will revert to 192.168.5.114, and you won’t be able to modify it (because you’ve connected the optical modem and disabled DHCP, triggering the issues mentioned earlier in the tricky parts). In this case, you’ll need to start over from the beginning (by powering off the optical modem).
Conclusion
That’s it! Along the way, I encountered some odd issues and made a few failed attempts—like why I thought of powering off the optical modem first, setting up the router, and then turning it back on.
Wishing you all WiFi freedom!
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From the author:
I often wish that when facing some key decisions in life, someone could tell me the best course of action so that I would not waste my precious time. Putting myself in others' shoes, I therefore write blogs often, hoping to record in this tiny corner of the vast Internet the once-in-a-lifetime experiences that matter to me, and to help those who seek help.
