How do you set up DDNS on a router? With this feature, you can connect it to your home computer and NAS anytime while you're outside

What is

DDNS doing: Your house number keeps changing

so first tell me I fell into this trap. Last year, I paired up a remote connection to my home NAS, and after more than a week, it worked pretty smoothly. One Wednesday at work, I tried to dig through a file, but the domain name just wouldn't connect. I thought the NAS was down, so I anxiously asked my family to check the lights, and the machine was fine. At night, when I checked the router's WAN port, the IP started with 117.136 and changed from 111.72 — the home broad network public IP is dynamic. If the carrier's data center cuts in one loop or the fiber modem redials once, the IP might change, but the IP I used when assigning the domain name is already obsolete.

DDNS is the solution to this. The logic is very straightforward: you register a domain name (like myhome123.xxx), and every few minutes, the router reports its current public IP to the domain service provider, who then resolves the domain to the new IP. How to change IPs? The domain name always points to it. You just need to remember the domain name outside, don't worry about how many times the numbers below have changed.

by the way, let's talk about the speed at which it takes effect. After changing the IP, the domain name doesn't follow up instantly; you have to wait for the router to report the next round, usually within a few to ten minutes. So if you can't connect outside, don't rush to conclude it's faulty—the optical modem at home has probably just redialed, so wait about fifteen minutes to try again. To determine if the IP has really changed, have your family member log in to the router's backend and check the WAN port. If the WAN port number doesn't match the domain resolution, it means the IP is changing during a gap period.

so DDNS, translated into plain language, is "giving the home broadband IP of the general moving house to a follower." If you want to connect to your home computer remotely, check NAS, or monitor monitoring remotely, these functions are basically the foundation.

start, confirm one thing: does your home have a public internet IP

skip this step, and everything else will be wasted. DDNS can only track public IPs. If you don't have one at all, no matter how well you set it up, you won't be able to get back. I wrote about three steps in my article about checking public IPs in : check the router's WAN port IP, turn on your phone to check the outgoing IP, and pair two numbers to one. If you match up, congratulations, let's move straight to the next step. If

doesn't match, don't panic. First, check if the WAN port IP starts with 100.64 to 100.127. If so, your home shares an exit with the entire building in the operator's intranet (CGNAT), which is a problem DDNS cannot cure. Two options: call number 10,000 to report "I have storage devices at home and need remote access," and get a public IP address. Most regions are free, just ten minutes away; If not, go for intranet penetration or IPv6. I've written in these articles about how to choose between frp, fn Connect, and IPv6 .

I was lucky—I made a phone call and was about to come back, and after that, the remote call never stopped. My colleague asked twice but didn't get it, then switched to IPv6, which was also stable.

various router brands, where to hide DDNS

confirm there is a public IP address, then you can proceed. The location of this feature varies significantly between brands. I've listed several brands I've touched:

ASUS is the easiest way: open the "External Network (WAN)" and open a DDNS client. The server directly selects ASUS's own WWW.ASUS.COM, you can set up your own hostname and get a xxx.asuscomm.com domain. The whole process is free, and you don't even need to register a third-party account. This is the one I got for my mother-in-law's house, and I haven't had any maintenance for two years.

TP and Mercury are the same template. After choosing a service provider, enter the account and password you registered with the provider, and save it. One change to note: the tpddns.cn domain service that came with the old TP firmware has gradually stopped in recent years. Don't copy the old tutorial blindly; the new firmware goes straight to the Peanut Shell account. Also, some new cloud router firmware has removed this feature, so you can't find DDNS in the background. If you don't want to stick to the router, then let's look at the device-side solutions.

Xiaomi has a unique pitfall: its DDNS recognizes WAN port IPs. If your Xiaomi uses it as a secondary router (with a layer hanging on it), the WAN port gets a private address starting with 192.168, so DDNS is basically a free setup. Xiaomi needs to be the main router, or the optical modem should be converted into a bridge for Xiaomi to dial the number, so it has a public IP to report. This feature is not available in the Mijia app; it can only be opened in the web backend.

searching the backend but still not finding a DDNS entry sign (Tengda home models are like this), don't think it's hopeless—the router can't do it, but the device at home that keeps running can do it. Install a Peanut Shell client or ddns-go on a NAS or an idle computer, and have it report the IP—the effect is exactly the same. The essence of this is "finding a constantly online machine to report your house number." The router is just the most convenient one, not the only one. If you have a NAS at home, this route is more flexible, and you can even attach scripts to your machine.

How to choose a free service provider: I've stepped into two pitfalls for you

Once you've picked out your router, it's time to register a domain name. There are only three free options to choose from, each with its own temperament:

one is a No-IP, a long-established brand. The free version comes with a domain name, but it has a famous rule: you must log in to the official website and click confirm every 30 days; if you don't click the domain, it will delete it immediately. Once, I traveled for over half a month, and when I came back, I found remote contact was missing. After two hours of searching, the root cause was that my domain had been reclaimed. Suitable for diligent people, or you can set a recurring reminder in your calendar.

one is Peanut Shell (Beirui), widely used domestically. Registering gives you a free domain name, which is more than enough for DDNS resolution. Here, it's important to distinguish between two things: 'DDNS resolution' simply points the domain to your home IP, and the traffic goes through your own broadband, with no limit on traffic; "Peanut Shell Internal Network Penetration" is the data-driven system, with a free quota of 1GB per month and speed limits. If you use port forwarding, use the former—don't be scared off by the 'free version restrictions.'

ASUS users mentioned earlier, asuscomm comes with it, so skip this step. Advanced OpenWrt players can use ddns-go, which can connect to Cloudflare, Alibaba Cloud, and others. Owning your own domain costs just over ten yuan a year, and the resolution speed is fast. However, this goes beyond just "tapping the backend" twice. Beginners should practice with the free tools first.

having a domain name alone isn't enough: you have the house number, but you still have to open the door

DDNS which door you enter, and only solve the problem of "finding your home" and forwarding through the port through which door you enter. These two are compatible. I've written about the specific method in the port forwarding and DMZ about universal standards. Mercury users this brand special . Three key points:

the mapped device first binds a static IP ( how to bind it is I have written). Otherwise, once DHCP drifts, the forwarding rules become void. My first white setup was here and I died. For external ports, use high-digit numbers, for example, external 18080 to internal 5244. Don't directly expose default ports like 3389 or 22, as the entire network scanner scans these every day. The account password must be at least 16 digits, and I wrote about the NAS being encrypted overnight by ransomware while running naked on the public network (DeadBolt the of that order). Once the door number is left, no lock is set, basically leaving my assets hanging by the roadside.

connect to the computer's Remote Desktop, don't forget two more steps on Windows: turn on the "Remote Desktop" switch in Settings, and make sure your Microsoft account password is too small. At my company, the desktop connected to home was just a domain name plus high-level port to 3389. I used it for over a year, and it was very convenient. When rushing to a solution, it was much faster than transferring files to a cloud drive.

these situations, there's no need to fuss at all DDNS

not everyone needs this feature. Let's take it personally:

just want to change your WiFi password and see who's freeloading when you're out? You can just use cloud management for various brands' apps (I wrote about Mercury's system in remote management ), TP, Mercury, ASUS, and Xiaomi all have them, zero configuration.

remote NAS but too lazy to fix ports? Official relays like Synology QuickConnect and Feiniu fn Connect can also be used. It's slower but doesn't require much thinking. How do you choose between DDNS and DDNS? I tested it in one . My suggestion is to have a relay minimum, have a public IP and then connect directly to DDNS, and have both as backups.

public IPs are absolutely unusable, go IPv6 that the road. Now the three major operators have already issued them by default.

Here's the complete order: check the public IP → If not, find a way to get or change the route → ASUS users can directly open asuscomm in the backend; other providers should first register Peanut Shell or No-IP → Fill in the account on the router's DDNS page → Bind the device to a static IP → Configure port forwarding (use a high-level port externally) → Strengthen the account password → Test it outside before the trip. The whole process takes less than half an hour. After matching this time, you'll never have to worry about changing your house number.