Improper setting of IIS causes the website to frequently drop

The unit web server is built on the city's e-commerce network, through the e-commerce network IDC and the Internet two-wire interconnection, and the export address uses the telecom IP. Recently received by users generally reflected, often can not open the unit website, check the user client, change the telecommunications DNS server address can be normal access, after a period of time need to change the DNS server address again, change the Netcom DNS server address without repeated changes . By looking at the logs, the server area has not been changed, so troubleshoot. 1. The switch and firewall in the equipment room are not abnormal. Users on the LAN and Internet users access other servers on the same network segment. The users on the LAN are pinging the server. The Internet users ping the server because the firewall security settings show that the resources are exhausted. This is the same as the normal situation. change. 2. There is no abnormality in the internal lines of the city's e-commerce network. After excluding the internal network of the equipment room, the network management of the e-commerce network reports the situation. The network management discovered the same problem after the local domain name and IP address of the local network, and found that other organizations have similar situations. However, the nodes are checked one by one, and the route is considered normal, and the allocated IP can normally point to the WEB server. 3. There is no abnormality in the two-line interconnection between the city's e-commerce network and the Internet. There are more than 300 large and small businesses in the city's e-commerce network. Most of the services can provide services normally. Only a few websites can not be opened normally, so the interconnection can be eliminated. In summary, the problem of routing within the e-commerce network is basically eliminated, and the phenomenon that the telecommunications DNS server is frequently replaced at the user end without replacing the Netcom DNS server is discussed, and it is determined that the telecommunications DNS server fails to resolve the domain name of the website. Occurs, so continue to investigate item by item. 4. Contact the domain name provider to modify the DNS resolution server address of the domain name. However, after modification, the phenomenon still exists. The domain name provider recommends contacting the telecommunications side to check whether the setting is disabled. 5. Contact with telecommunications. After two days, the telecom feedback DNS resolution is normal, and there is no restriction on the domain name. At this point, all network lines are reported to be normal, but the phenomenon has not been eliminated. Through careful analysis, it is found that there are three websites running on the same server at the same time, and the other two websites can access normally, which eliminates the problem that the telecommunications DNS resolves the domain name, which should be a problem on the server. Open the server IIS, carefully check the settings of the three websites, and finally find that the faulty website not only has the intranet IP address of the domain name in the advanced website logo, but also retains the dual-line IP before the e-commerce network did not replace the IP. Ping these two IPs, telecommunications has expired and Netcom can still be used, so the reason is found. Looking back at the entire troubleshooting process, everyone's focus is on the binding of the domain name to the existing public IP, and the two IPs in the host header are used for the smooth connection of IP at the time. The network has deactivated the original telecom IP. The telecom DNS server cannot resolve the IP and resolve it through the Netcom DNS server. The Netcom DNS server discards the packet if it cannot guarantee its own resolution, which causes this phenomenon to occur. After the two identifiers are deleted, everything returns to normal, and the number of hops after the Tracert domain is greatly reduced, and the access speed is accelerated.