Should you turn off the router UPnP? After I turned it off, WeChat video went on strike first. After checking the mapping list, I finally understood what it was secretly doing

did something foolish last month. I came across a post about home network security, claiming that UPnP is an 'automatic door opener that opens the back door,' and suggested turning it off completely. The accompanying image even marked it in red as 'high risk.' That night, I logged into the 192.168.1.1 backend, turned it off, and felt very comfortable sleeping. The next day, my mom called on WeChat video. When I answered, there was only sound and no picture. No matter how I tried to fix it, the screen went black.

struggled all night before realizing where the problem lay. This article breaks down UPnP and clarifies it: what it does, what damage will it cause when shut down, is the risk really that scary, and if it really shuts down, how will you lay the groundwork behind?

to speak plainly: UPnP is the little worker at home who opens the door by himself

UPnP stands for Universal Plug and Play. The name sounds mysterious, but the task is very simple: have the devices at home apply to the router to open the door themselves.

to give an example. Your router is a very secure neighborhood. Data trying to connect to PS5 or transfer files via NAS is always blocked at the door. When there's no UPnP, you have to register at the security office yourself—go to the backend and manually set port forwards one by one, telling the guard, 'If you want a PS5 in the future, enter through door 3478.'

having UPnP is like hiring a delivery worker in the community. PS5 boots up and needs to play online, so I handed over a note: "Open a door for me, port 3478, use until midnight tonight." The router automatically registers the note after reading it and automatically delogs after use. You don't need to step in the whole process.

home has more devices than you think that this worker relies on for daily living: WeChat video calls, PS5 and Switch connection, BT downloads on NAS, media sharing on Windows, automatic printer discovery—all regulars handing out messages. They usually stay silent, but when you dismiss the helper, you'll find out who's swimming naked.

the night I turned it off, three things broke

looking back at that night's "accident scene," the damage was not just like WeChat videos; it was just that my mom's call came the fastest. I checked each one and gathered three items:

• WeChat video calls: No sound, no picture, switching WiFi or 4G is the same—no, 4G is good, only if your home WiFi is broken, that's not about the phone;
• PS5 Online: Tested NAT type, dropped from Type 2 to Type 3, searched for rooms in the game but couldn't find it;
• Synology NAS Drive: When I connect my phone to the home sync drive while outside, it keeps spinning and won't get in, but QuickConnect still works.

three things have nothing to do with each other; the only thing they have in common is: all need to be temporarily opened by routers, and the security guard fires the helper that night.

I reopened UPnP, and in five minutes, all three were restored. This switch is inconspicuous in the background, but there are more things hanging underneath than you might think.

check backstage: Who is your door open for

Before you

shut down, I suggest you do one thing first: check the backend and see how many doors UPnP has opened right now. Most routers have a mapping list that is clear at a glance. I've touched the entrances of all brands:

My Xiaomi AX3000T has 11 apps hanging all year round: 5 on my PS5, 2 on WeChat, 3 on Synology (all via BT download request), and 1 on the printer. Each entry shows which device, which port, and when the application was made.

this list is the basis for judgment. If you find a bunch of unfamiliar device names, or external ports are opened randomly and extensively, you really need to be cautious. But if the list is clean and only shows a few pieces of their own equipment, it means the laborers are doing their jobs properly.

risk is a bit exaggerated online, but it's not unfounded

be fair. The risks of UPnP are real, and the principle isn't complicated: the mapping it opens hangs on the router's WAN port, and the scanner outside can scan these open ports. If the device behind the door itself is poor—for example, the camera still has the factory admin password—then the lock is basically made of paper.

most famous case is the 2016 Mirai virus, where hundreds of thousands of cameras and recorders were swept out to form a botnet, and a wave of attacks that paralyzed half of the U.S. network. But if you dig into the details, you'll find that all those devices have admin/admin weak passwords, with the main responsibility being on the devices themselves. UPnP just makes scanning easier.

So my view is: afraid the door will be pried open, replace the lock first, not weld the door shut. camera passwords should be changed (I previously wrote about monitoring networking specifically about this topic, how to plan for installing cameras at home IoT device firmware needs to be upgraded. Once these are done, keeping UPnP is not really leaving the back door open.

really shut it down in one go, which would be the kind of accident I mentioned above. And here's a pitfall: if your home uses the optical modem in router modem and the router is mounted under the optical modem, UPnP only works on the router layer, with a door pressing outside, so many functions are already uncomfortable—this is a two-layer NAT issue. I wrote in detail in my NAT that the solution is to switch the optical modem to a bridge, which is a different matter from whether UPnP is turned off.

Zhen decided to turn it off: first, lay the groundwork for these devices

if you have old cameras and a bunch of generic IoT devices at home and can't be bothered to reset passwords one by one, then UPnP is definitely a worry-free safety net. But before shutting down, make sure the equipment that depends on it has a backup plan, or else that's what happened to me that night:

Step one: follow the mapping list above to list the frequent customers who send you notes. Step two: bind these devices to static IPs; otherwise, there's nowhere to forward them on the ports—the DHCP land lease will drift. I've written an article on binding static IP to 192.168.1.1 for specific methods—just follow the instructions. Step three: manually forwarding ports to the top, which means you quit your job and sit in the security room yourself. Which ports does the PS5 need, and what are the differences between forwarding and DMZ? You can copy the table from the on port forwarding and DMZ for .

NAS users are relatively easy to handle. Synology's QuickConnect and Feiniu paired with frp both rely on cloud relay and naturally don't rely on UPnP. Even when closed, it doesn't affect remote access much. I compared the three in my post NAS my home in Wailian.

some devices don't need to be managed at all: cloud storage cameras that only use the Mi Home app, smart speakers that run through server relays—all their data flows through the manufacturer's cloud, and whether the router opens the door or not doesn't matter to them.

to turn on or off, judge accordingly

give a direct answer at the end. Matched by family situation:

how to isolate anti-anti-internet and visitor networks, the complete steps in the previous anti-anti- article. I've also compiled an article on the comprehensive beginner security checklist (changing management passwords, turning off remote management, etc.). I've also compiled an article 5 things to do after logging in, specifically telling UPnP beginners not to move for now—now you should understand why it's written that way.

Wrap up with a clear order: First, go backend to check the mapping list and have a clear idea; Then change the weak password, upgrade the firmware, and make the lock stronger; Then use the table above to decide the switch; If it really turns off, it paves the backline for static IP and port forwarding for the console and NAS. Don't be like me—just click to close a post after reading it, and the next day my mom will teach you how to handle things.