What should I fill in for the router’s DNS server? 114.114.114.114 and 223.5.5.5 I tried it for half a year, and finally the whole family used this

At that time last year, the broadband speed at home was obviously over 900 Mbit/s, but when I opened a web page, the screen would often go blank for a second or two, and the video would start to spin in a circle. At first I thought the router was old, so I reset the ZTE Xantian AX3000 twice, but the problem remained the same. Later, I ran a group using the computer nslookup Only then did I realize that the problem was not the Internet speed, but the step before opening a web page - the router asked me the DNS. If the query was slow, it would be useless no matter how fast the subsequent downloads were.

This article is not going to talk about big ideas, but just explain the results of my half-year hard work.: What exactly should be filled in the DNS server box in the backend of the router? What are the differences between the four sets of DNS? Which pitfalls have I encountered?

Why does DNS make the Internet "seem" slow?

Let’s start with an analogy. You type in the address bar www.baidu.com , the computer doesn’t recognize this string of characters, so it needs to find someone to find out which IP address this URL corresponds to. The server that helps with translation is DNS. The two lines "Preferred DNS Server" and "Backup DNS Server" in the background of the router are who you designate to do this.

Many people think that the webpage cannot be opened because the network is disconnected. In fact, sometimes the bandwidth is not used at all and is stuck at the DNS step. I use nslookup I have tried using the operator's default DNS for the same domain name, and it often takes up to 1 second to return results. ； Replace with 114.114.114.114 , it will come back basically in 20 to 40 milliseconds. This second of slowness is inconspicuous at first glance, but if a webpage needs to check more than a dozen domain names before and after, it will be obvious when added together. How does DNS work? I was there before What does DNS resolution mean? I have already dismantled it, so I won’t repeat it.

Therefore, the box in the background of the router is not just left blank. Leaving it blank usually means automatically using the DNS issued by the operator. It can be used, but it may not be fast or reliable.

I ran all four sets of DNS for more than half a month

In order not to be biased by the day's network fluctuations, I used the TP-Link TL-WDR7660 Gigabit version and desktop computer at home for more than half a month. The testing method is not complicated: Run it once during the day and night, and use it every time ping Make 20 packets to see the average delay, and then use nslookup www.taobao.com 指定DNS Look at the parsing return time. The computer network card is the Realtek RTL8168 that comes with the motherboard. The network cable is directly connected to the router. I also took the time to compare the mobile phone traffic set, and the conclusion is similar.

The following set of common values ​​I wrote down are in milliseconds, the smaller the better.

Two things can be seen from the numbers. First, the operator's DNS is indeed the closest to your home, and the ping only takes a few milliseconds, but it occasionally resolves very slowly. This is the source of "you have to wait for the Internet connection". The second is 8.8.8.8 If it is too far away, the delay is often an order of magnitude higher than that of domestic DNS. Do not use it as an acceleration tool for ordinary households.

The operator defaults to the fact that the biggest problem with DNS is not slowness, but redirection.

My family has been using automatic distribution from the operator for the first time. What really made me decide to change it was not the occasional delay of a second or two, but the hijacking. There was a time when I opened an expired URL on my home computer and was often redirected to a promotion page. ； What's even more disgusting is that if you occasionally enter the wrong domain name, instead of reporting "not found", you will jump to a search page with advertisements.

The technical fault for this kind of thing lies in DNS. You give it the domain name to check, and it deliberately returns a different IP to you, and the browser will obediently jump to it. Some places will also insert scripts into web pages, or change shopping links to provide rebates. This is no longer a matter of speed, but a matter of "the person asking for directions deliberately points you the wrong way."

Of course, not all operators' DNS does this, but I have lived in two cities and encountered similar situations with the default DNS of two broadbands. Later, I manually wrote the DNS in the router as 114 and 223, and the jump almost never appeared again. This incident also reminds me that if the web page opens incorrectly, don’t blame the computer first. First, check whether the IP returned by DNS is correct. Want to understand the output, How to read nslookup output This article can be read side by side.

114, 223, Tencent, how to choose among these domestic companies?

Spreading out the domestic public DNS, I use these three the most.: 114.114.114.114 , 223.5.5.5 , 119.29.29.29 . Each of them has a backup address. I am used to not filling in the same address for the primary and secondary addresses, such as the first choice. 114.114.114.114 ,spare 223.5.5.5 , In this way, one family can temporarily have a seizure, and the other family can take over.

114.114.114.114 The backup is 114.114.115.115 , is characterized by stability, but its DNS-over-HTTPS and other encryption capabilities are average in my impression. 223.5.5.5 The backup is 223.6.6.6 , Alibaba has good stability and fast response. You can also use it to check some contaminated domain names with some differences. Tencent's 119.29.29.29 and 119.28.28.28 It's also stable, I put it in the second backup position. Don't fill in the same IP as the primary and secondary IP addresses, otherwise the secondary IP address will be in vain.

If the router supports IPv6, Ali IPv6 DNS is 2400:3200::1 and 2400:3200:baba::1 , Tencent is 2402:4e00:: . However, in most home scenarios, it is enough to fill in the correct IPv4 first. Don’t mess with both stacks at once, as this can easily cause trouble for yourself.

There is another practical problem: Public DNS is not a panacea. What it solves is "faster query and less hijacking", but it cannot solve the problem of packet loss in the broadband itself, WiFi interference, and website server card. Don't change the DNS every day when the network is slow. Run a speed test first and look at the network speed and resolution separately.

8.8.8.8 Don’t fill in blindly, these two pitfalls are very practical.

I saw it in the background of an old router. Someone filled in the DNS as 8.8.8.8 and 8.8.4.4 , asked him why, he said it would be faster online. As a result, opening domestic video apps was even slower. This is the first pitfall I want to remind you of: 8.8.8.8 The servers are basically abroad. Domestic home broadband direct connections have high latency in the past, and the CDN nodes it returns are often overseas-oriented. When you download domestic videos, you may be directed to a long detour.

The second pitfall is that Google’s DNS access in the country is sometimes unstable and sometimes times out. Don't underestimate this, once it is set up on the router, all devices in the home will use it. I helped people change it back that time, and changed it to primary and secondary 223.5.5.5 and 119.29.29.29 , the video rotates significantly less.

If you care about privacy and don't want the operator to see what domain name you checked, you can go in the direction of encrypted DNS, which is DoH or DoT. However, that requires additional configuration, and it cannot be used simply by filling in the IP address in the router. I am here What does encrypted DNS mean? As mentioned in the article, the query of ordinary UDP 53 is like a postcard, the content is visible. Changing the public DNS only changes the recipient, which is not the same as putting the postcard into an envelope.

8.8.8.8 It’s not that you can’t use it, just don’t fill it in with your eyes closed. If you really need external network resolution, you can temporarily specify it on a single computer. Don't hang up all the equipment in the whole family.

My final filling method and the three checking orders

My current unified main router settings for the entire family are as follows:: Preferred DNS 114.114.114.114 , fill in the backup DNS 223.5.5.5 ； optical modem maintains the bridge connection and does not allow optical modem to get involved again. After modification, execute it on the computer first ipconfig /flushdns , and try reopening the webpage. This cache clearing action cannot be omitted, otherwise the computer will still use the old analysis results.

Why not fill in the operator first? Not because it is necessarily bad, but because I think it is sometimes fast and sometimes slow, and I even got hijacked. If your operator's DNS is always clean and the ping latency is low, then it's no problem to continue using it. Don't take other people's "best answer" as your answer. The Internet varies greatly from place to place.

The following is the troubleshooting sequence I recommend when the network is slow or the web page cannot be opened. Following it is faster than changing DNS back and forth.

• First confirm whether the broadband is available: The lights on the optical modem and router are normal. Can the wired speed test reach the end of the broadband range? ； The cable is too slow, and even changing the DNS can’t save it.
• Check the DNS again: on computer nslookup www.baidu.com Check the return speed, and then specify 114 or 223 to check again. ； If the default is slow and the specified speed is fast, go to the router and change the DNS.
• Finally check the device and WiFi: Is the mobile phone connected to 5G or 2.4G? Is the router occupied by heavy downloads? This layer has nothing to do with DNS, don't mix it up.

After changing the DNS, you don’t need to change it frequently. I only changed the main and backup order once in half a year, and the rest of the time it was stable. What really needs to be changed is the blank or wrong location in the router, rather than chasing the "fastest DNS" every day.

One sentence to end: DNS of your home router, fill in first 114.114.114.114 add 223.5.5.5 , don’t fill in the same one for primary and backup, don’t fill in the blank 8.8.8.8 . To verify whether it has taken effect, clear the cache first and then retrieve it. nslookup A glance at the return is more reliable than physical sensation.