About the DNS proxy function of a Broadband Router

Concerning the DNS proxy function of a Broadband Router, mobile staff came to the organization one day to eliminate network faults, and accidentally found some doubts, that is, if the DNS server of the Local Computer ip address is set to the address provided by mobile or the address of the local route, the website can be resolved and accessed normally. Can the router also use the DNS service? Www.2cto.com is very strange. The following information has been found on the internet for a long time. It may be explained that broadband routers generally have DNS proxy functions. The so-called proxy means that it does not have DNS resolution functions, but it can help you complete the parsing task. First, a Broadband Router is a NAT principle. It consists of two IP addresses, LAN gateway IP addresses and WAN ports, to connect to the Internet, after a vro is assigned a number, two DNS servers are obtained from China Telecom, China Netcom, and China tietong. This has nothing to do with the IP address set by the local machine, basically, this DNS is a dns ip address that China Telecom, China Netcom, and China tietong think can be properly resolved. Now let's talk about how DNS works when a PC using a Broadband Router sets the dns ip address as a lan ip Address: DNS request package ---> lan ip ---> is the real dns ip address (the main dns ip address obtained from the WAN port). When the PC is set to the local public dns ip address, the DNS works as follows: DNS request package ---> genuine dns ip (the primary dns ip address set on the PC) www.2cto.com From the above we can see the difference: when using the proxy, you need to take another step, the DNS request packet is first sent to the broadband route, and then the router sends the request packet to the destination dns ip address (there is a packet settlement process here). Instead of using a proxy, DNS data packets are directly sent to the destination dns ip address for resolution. It is because the proxy principle of the Broadband Router is not very stable (BUG) when packets are unwrapped ), can cause sometimes resolution and sometimes cannot be resolved (of course, this should exclude the target DNS server itself to work normally ). If so, it is better for network administrators to stay away from laziness. When configuring the address pool, add the Internet DNS to reduce the routing burden and improve network stability.