Original link: https://blog.codingnow.com/2022/10/telecom_ipv6.html
I was tossing around BT downloads at home on weekends and found that UPnP couldn’t work, so I went to Guangmao to see what was going on.
I found that the telecom broadband is already dialed by the optical modem by default, and the router at home is used as a secondary router. If you want UPnP or DMZ to work, you need to set it in the optical modem.
Check the default administrator password printed on the light cat device to log in, but I didn’t find too many setting options. Searched on the Internet, you need a super administrator status to see the full settings menu. The general saying is to call and ask the master who installed the broadband, but it’s getting late, and I don’t want to trouble people. On second thought, there are so many broadband devices to manage, telecom should use a unified password, or there are some simple means to get this password. Otherwise, the cost of establishing a whole management system is too high.
According to the google search result, after opening 192.168.1.1/cgi-bin/baseinfoSet.cgi, the password is written in this json file. Although it is not plaintext, it is almost the same as plaintext. The numbers written in the password entries are ascii inflections. Because the normal password is known, it’s easy to see the rules: a small number is an ascii code, and a large number is an ascii offset of 4. A line of lua code can be converted to the original text of the password.
After getting the super administrator password to enter the management interface, you can open port mapping functions such as DMZ. But I found that telecom no longer gives ipv4 public network address, even if port mapping is done, it is useless. According to the online saying, you can call Telecom and ask for a public IP, which will generally be readily available. But one is that it is too late, and the manual customers are not online; in addition, according to the latest statement, it is difficult for telecommunications to obtain public IP in the past two months. Think about it, IPv4 address resources have been exhausted for a long time, so let’s take a look at IPv6.
In the settings menu of the light cat, you can see that the IPv6 address has been obtained. My secondary router is Xiaomi AX9000, which is relatively new. Log in to see it. It also supports IPv6, but it is turned off by default. Change to IPv6 Native mode, use https://test-ipv6.com/ to test it, and find that the ipv6 address cannot be obtained; then change to NAT6 mode, and this time it works.
But it feels like it’s a joke to use NAT in an ipv6 environment. Isn’t it good that every device should have its own ipv6 address? The test result is that the ipv6 address of the Xiaomi router is seen externally, not the one of my local device. This must be due to NAT, my devices are all hidden in the LAN behind the router’s NAT.
That is to say, the optical cat is currently correctly connected to the ipv6 network, obtains an ipv6 address prefix, and correctly assigns an independent ipv6 address to the Xiaomi router behind it. But when the native mode is enabled on the Xiaomi router, it can no longer apply for a sub-prefix to the light cat. Therefore, it is impossible to use the function of assigning an independent IP to the lower-level device (the optical modem as a router can only assign a unique ipv6 address to each directly connected device, and cannot assign a prefix). There is also a third way to obtain the ipv6 address on the Xiaomi router, which is to fill in the static ip by yourself. Thinking about it is unreliable. If the light cat reassigns the address, I have to change it manually, so I didn’t bother.
There are only two paths left:
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Change the Xiaomi router to wired relay mode, which means that the devices plugged into it are directly connected to the optical modem, so that the optical modem can directly assign IPv6 addresses to them.
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Change the light cat to bridge mode, use the Xiaomi router to do the first-level routing, and dial up the Internet directly. In this way, the Xiaomi router can directly obtain the IPv6 prefix from the operator, which can then assign the IPv6 address to the following devices.
In view of the performance of Xiaomi AX9000 is obviously better than the optical cat sent by Telecom, I tried scheme 2 first.
Because I already have the super administrator password, I don’t need to contact the telecommunications master to help me change the bridge mode. I looked at the existing settings and found that it is not the dial-up Internet access method of PPPoE, but IPoE, and there is no user name and password. In IPoE mode, bridge mode cannot be selected.
With the idea of giving it a try, I changed back to PPPoE and chose the bridge mode; thinking that if it doesn’t work, I’ll change it back. After trying it, I found that I can’t connect to the external network, and then I changed it back to let the optical modem do the routing and dialing, but I still can’t connect. From the setting interface, the optical fiber is connected and the device is registered correctly, but the DHCP can not get the address.
I had to use my mobile phone to file a repair report on the telecommunications website, shut down and go to sleep.
10000 called me back early the next morning. The customer service said that my home network is connected, but the dial-up password is wrong. I thought to myself, didn’t you change me to IPoE certification? Why do you need a password. Besides, I tried password authentication last night, but I couldn’t dial it.
The telecom customer service told me that it found that the broadband in my home was in the PPPoE dial-up mode, and asked me to try again. I guess it’s the telecom side that has updated the settings remotely. Then I turned it on and tried again, and sure enough, I was connected to the external network.
After testing it, the desktop finally has its own IPv6 public network address ?
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