Mercury router settings DNS, the entrance is hidden in the WAN port advanced parameters

Last week, my cousin asked me on WeChat whether he wanted to bind a MERCURY ID to his Mercury D191G so that he could remotely manage the router through the mobile app (I have written about what can be done after binding) Mercury remote management ), after entering the account password, the interface keeps popping up "Request failed, please try again later." I called customer service and they said, "DNS may be unstable. Try changing the DNS on the WAN port." He was there. melogin.cn Scroll through the WAN port settings - flipping through it, the page only has Internet access methods, broadband account passwords, and no place to fill in DNS at all.

I also went to the wrong place on my first trip. Mercury's DNS fill-in box is not on the main page of WAN port settings. It is hidden under the "Network Parameters" menu called WAN port advanced parameters in the subpage. This article will explain clearly the complete path of changing DNS on Mercury, how to choose DNS, and the pitfalls of not taking effect after changing.

Let’s talk ugly things first: DNS controls translation, regardless of speed

DNS does one thing: You type in a URL and it is responsible for translating the URL into an IP address. It's equivalent to a directory assistance desk. You give your name and it gives you your phone number.

So the diseases that can be cured by changing DNS are:: Some websites cannot be opened, domain name resolution errors are reported, and the router cannot connect to the manufacturer's cloud server (my cousin's MERCURY ID problem falls into the last category). It is also clear that the diseases that cannot be cured by changing DNS: Download speed will not increase by one point . My cousin’s home has 500 MB broadband. Before changing the DNS, the speed was measured at 486 MB, and after the change, it was measured at 483 MB. The fluctuations between these two and three MB are Speed ​​test The error itself is not the result of DNS. Those posts on the Internet that "changed DNS and doubled the speed of the Internet" probably mistook "the web page opens faster" for "the bandwidth has increased" - the web page is faster because the half second of parsing is saved, not because the water pipes have become thicker.

What is DNS and how to choose a public DNS? I am here DNS configuration article It is written in more detail. This article only talks about the operations and pitfalls of Mercury.

My troubleshooting order: First confirm that it is DNS that is to blame before taking action.

Before changing the DNS, I asked my cousin to do a comparison to avoid going to waste. Open the command line on his computer and type nslookup mercurycom.com , look at the returned server address - this step is to check who is currently using DNS. Normally, it should return the DNS address issued by the operator plus a string of parsing results. The parsing results returned by his station were intermittent. The same domain name was checked three times in a row, and the results were obtained twice and timed out. This is what the customer service said: "DNS is unstable."

By the way, if "some websites cannot be opened and some can be opened" in your home, it is also worth checking. But if All websites cannot be opened, and WeChat cannot be sent. , that is not a matter of DNS. First check to see if there is a network outage due to arrears or a line problem. Don’t mess around with DNS.

Another reminder: My cousin uses this as the main router. If you change the Mercury router to an AP or use it as a switch (LAN port cascading), no one will use the DNS of the WAN port - it will not dial up, and the DNS will be managed by the superior device. At this time, changing the Mercury router is in vain, and you have to go to the superior router or optical modem to change it. How to change the optical modem side, I wrote an article Telecom Optical Modem Modifies DNS , most of them require super-management permissions, which is much more troublesome than the Mercury one.

real entrance: WAN port advanced parameters under network parameters

Computer browser knock melogin.cn (If you can’t open it, knock 192.168.0.1 , the two are the same door, I really can’t go in and take a look. Can't open the troubleshooting article ), enter the management password to enter the backend. Then follow this path point:

Advanced settings → Network parameters → WAN port advanced parameters

On this page, there is a box for "DNS Server". Fill in one for first choice and one for backup (officially, fill in at least one), and click Save. I filled in the first choice for my cousin 223.5.5.5 ,spare 119.29.29.29 , after saving the page, you will be prompted to restart or automatically reconnect, and wait for it to finish transferring. Then go back to the upper right corner of the background and click MERCURY ID to log in again - this time it is connected, and the router is also online in the App.

The two places where it is easy to stumble are mentioned above.:

One is Don’t look for it on the WAN port setting main page. . The WAN port settings page of the old and new firmware only has Internet access methods and broadband accounts, and DNS is not there. If your backend doesn't even match the menu tree of "Advanced Settings → Network Parameters", it's probably an old firmware with a different interface. Go there first Upgrade firmware Looking back again, Mercury with the old interface usually has two columns of preferred and backup DNS at the bottom of the "Network Parameters → WAN Port Settings" page, with the same logic.

The second is Can’t change it in the mobile app . Parameters such as "Internet Settings" in the Mercury WiFi App are read-only and can be viewed but not moved. Modifications related to network parameters such as DNS must be returned to the web background. This is the same as Xiaomi. I can’t find DNS settings in the Mijia App. The article about Xiaomi changing DNS Mentioned here.

Which DNS to fill in?: My measured delayed account

Before filling in, I pinged the commonly used public DNS at my cousin’s house one by one to give you a reference (his home is a telecommunications broadband, and there will be some differences between different operators in different regions):

I only have one suggestion for the main and backup combinations.: Alibaba is the first choice and Tencent is the backup. This combination works well for most domestic routes. 114 This old DNS is quite controversial. Many people on the Internet have reported that the results it parses occasionally point to promotion pages. It is worth taking a look at the small ads in the lower right corner. DNS hijacking self-examination That article, don’t rely solely on DNS selection. Google's computer has high latency and loses packets from time to time, so it's too troublesome to use it as a backup. AdGuard is used to filter ads. It can indeed reduce the number of banner ads in the browser, but the delay of more than 90 milliseconds results in an experience where the web page first opens half a second. It should be chosen carefully if there are elderly people at home - they can't tell which is more serious: "no ads" or "the network is stuck".

There is another invisible pit that I should mention.: If your home has enabled IPv6 (I have written how to enable it on the Mercury) The IPv6 article ), the mobile phone and computer may be using the v6 DNS path, which is still in the hands of the operator. The performance is that the DNS of v4 has obviously changed, but some websites are still the same. The way to judge is to see if there is a v6 address starting with 240e in the WiFi details of the mobile phone. If there is, either set the v6 DNS to automatically follow, or simply turn off v6 and compare it for a few days. This Daodao 922 article also mentioned in the optical modem article that the root causes of the two families are the same.

Did the change take effect? Check three places one by one

First check device cache . Command line on computer ipconfig /flushdns The easiest way to clear the local cache on your phone is to turn off WiFi and reconnect. My cousin said on the first night that "no change has been made". I took a look remotely and found that the DNS cache of his laptop still contained old records from half an hour ago. After clearing it, it became normal immediately. Devices such as TV boxes that cannot change their settings will be powered off for half a minute.

Second check Is there really a reconnection? . Mercury will reconnect itself after the WAN port is saved, but if you refresh the page at the moment of saving, the reconnection may not be completed. Go to the backend home page to check the running status of the WAN port. It only counts if it is "connected" and running traffic. If you are not sure, unplug the power and restart the router.

Third check Has the terminal manually set DNS? . The router's DNS only handles "automatically acquired" devices. If any of your computers have filled it out manually before, 8.8.8.6 In this case, it doesn't care about the router at all. Even if the router is changed, it won't care about it. command line ipconfig /all Look at the "DNS Server" line, it shows the address of the router ( 192.168.0.1 This type) indicates that it is managed by the router.

ending: Who is worth changing and who is just a toss-up?

There are only three situations worth taking action:: Some websites cannot be opened intermittently, the router keeps failing to connect to the manufacturer's cloud service (MERCURY ID, "request failed", etc.), and you want to unify FamilyMart's analysis and use AdGuard to filter ads. After these three changes, you can really feel the difference.

If you just have nothing to do and want to "optimize", my suggestion is to stop. Operators assume that DNS is not as bad as in earlier years. It is fast and stable in most areas. The benefits of changing public DNS are often within the margin of error. And there is a backlash for people with bad memories.: After two years, I changed the broadband operator or reset the router to the factory. I forgot to change the DNS. It would take an extra hour to detour when troubleshooting. I put a note on the bottom of my cousin’s D191G, saying "DNS has been changed." 223.5.5.5 」.

Last in order: First nslookup Confirm that DNS is the fault → Enter melogin.cn → Advanced settings → Network parameters → WAN port advanced parameters → Fill in the preferred option → Save and wait for reconnection → Clear the device cache → Verify again. If it gets worse after the change, just clear the box and resume automatic acquisition, and you can return to the original state in a minute. There is no regret medicine in this matter - you can regret it at any time.