Remember network practice

Spring Festival to Uncle's home, just he let me look at his home network, a bit of a problem, the general situation is as follows:

Dial-up Internet access, the outside of the network cable, connected to the LAN port of the wireless router (not WAN port), another LAN port out of the network cable attached to the computer, the computer can surf the internet, the phone can receive WiFi but not the Internet, each time the computer is switched on to dial to the Internet.

The first problem, wireless internet is not easy to solve, as long as the cable from the outside to connect to the wireless router WAN port. The original way to connect is simply to treat the router as a switch, not as a wireless route.

A router that has an empty WAN port, only the function of the switch (preferably shutting down the DHCP function of that router).

However, this set up after the phone is still unable to surf the internet, at first I still do not understand, and then slowly toss, understand, originally the network is using the PPPoE protocol (simple point is the need to dial to the Internet), then the computer dial a natural can surf the internet, mobile phone can not dial AH. So the workaround is to have the router go to dial. Enter the router settings interface, the WAN port connection type from static IP to PPPoE, the account password will appear in the input box, input can be.

After this setting, the computer end will not be able to dial on the internet, in addition to the phone can also access the network normally.

You can have the router go to dial, set the router's WAN port type to PPPoE.

The second problem comes, my phone can access the network normally, but the computer and uncle's mobile phone speed is very slow, access to a small number of Web site speed is normal, most of the Web site is very slow to open. Tossing for a while, the initial guess is the DNS problem.

First take the computer to do the experiment, the computer's DNS address and the alternate DNS address is not automatically assigned, but 2 fixed IP. It should be the wrong DNS address, but how do you know the correct DNS? I use 360 of the network repair function, it successfully changed the computer's DNS and alternate DNS address to another 2 IP values, the computer can access the network normally.

Why need alternate DNS address--dns redundancy

resource records for a zone are updated manually or automatically to the primary DNS server, and the secondary DNS service is designed to prevent the primary server from being inaccessible or down. The secondary DNS server periodically communicates with the primary DNS server to ensure that its information remains up to date. If it is not up-to-date, the secondary DNS server obtains a copy of the latest information from the primary server, known as zone replication.

So, how does the phone modify DNS? See Android phone How to modify Dns,iphone How to modify DNS settings. Originally, the domain name of Android phone 1 is the DNS address, how so bad, I looked for a long time, embarrassed.

In fact, the best solution is to configure the router's DNS and turn on the DHCP capabilities of the router. The DHCP function of the router is used to dynamically assign Ip,dns, gateways to devices connected to the router (originally I always thought that only dynamic assignment of IP).

At this point, the problem is all resolved. However, I still need to understand the following question, P.S. Windows-based

1, why the DNS address error, you can slowly open some Web pages or QQ, but most of the situation is not Internet access?

Originally, QQ communication mechanism does not rely on DNS server domain name resolution, and when the DNS address error, the DNS server configured by the device does not know the IP address of the URL you entered, then it requests the root name server, the root name server tells it the URL corresponding to the two-level domain name server, Let the DNS server contact the name server to obtain the appropriate IP. At this point the DNS server caches the information and the second request is a little faster. So, slow is because the whole request process is too long. And my phone started when the reason for the normal access to the network, should be my phone's own DNS address is correct.

2. How to scientifically and quickly determine if it is a DNS failure under Windows?

command line Input nslookup, and then enter your URL, if the normal display IP address, then DNS is correct, otherwise DNS failure.

3. About the Hosts file

When a computer accesses a website, the DNS server first resolves the network domain name to an IP address, so that our computer can access it. If each domain name request waits for the domain name server to be resolved and returns the IP, the access speed will be slower, and the hosts file can solve the problem. Before a DNS request is made, the Windows system checks to see if there is an address mapping relationship in the Hosts file, and if so, calls this IP address mapping if no domain name resolution is presented to the DNS server.

Location: C:\Windows\System32\drivers\etc\hosts

4. Why is the Hosts file not successful after modifying it?

• Modify Write permissions
• Note the effects of HTTP caching and DNS caching

  • For HTTP caching: The simplest method, an unreachable URL

  • For DNS caching: DNS Refresh

5. How to refresh DNS

command line input Ipconfig/flushdns.

6. How to get the correct DNS

• 360 ...
• From the telephone to the local network service provider (Telecom, mobile ...) ）
• 114.114.114.114

Remember network practice