This article is mainly about the router DNS setup failure, how to solve.
First, the phenomenon of failure
The network is not normal, feel the Internet is slow and intermittent, turn on the computer on the Internet speed is very slow and quickly like disconnection, unable to access the server.
Second, failure analysis
Troubleshooting Discovery VPN Device is connected to the router's switch port, because there is no interface temporarily connected to the router's switch port, it may be the device's Routing and Routing and forwarding path conflict, resulting in routing resolution is not normal.
Third, the failure to solve
(1) using network cable to the VPN access switch, broken network fault solved, but the internet is still very slow, performance for the first time to log in to the site requires 5-10 seconds of waiting time, and the second time to open the same page will be much faster. But open the lower page or other pages is still very slow, view the routing list all domain name resolution has been forwarded, and the domain name resolution is normal, but ping some web site delay some long.
(2) At this point we want to open the DNS Proxy service on the intranet interface, using the following command:
1, first of all the routers in the front four ports to a routing port
2, Inter E0/2 E0/2 is to change the port number port mode route
This allows the routing function of the port to open DNS resolve.
(3) Through the Web to configure the intranet port, at this time in the Web configuration interface, to find the interface configuration-wan interface settings There will be four WAN interfaces, when configured like an extranet port, set IP address for intranet port, external network DNS server, set complete, then the Internet test, At this point the failure disappeared, the speed of the Internet is normal.
Fault reason is intranet Port DNS service agent default is not open, the intranet to the router to send resolution request can not immediately get router intranet port response, all domain name resolution through the extranet port to find public network DNS to resolve, resulting in DNS resolution response is very slow.