Due to the complex enterprise LAN network environment; the number of terminals, the number of devices than more; they would often Caton network fault. Once the network slows down, the face of complex network environment, network management and technical personnel need to quickly and accurately diagnose the problem lies, and to solve them. In this paper, I will try to describe the common causes and diagnosis of network card becomes slow. In general, the reason the network Caton has the following areas:
Extranet reason: the operator line failure, insufficient bandwidth, routers and other hardware and software failures.
Intranet reasons: equipment failure, network settings such as the network reasons.
So off the network, the network card suddenly, the first step is to determine the problem, including the network or outside the network, and then subsequent diagnosis.
1. First, diagnosed by ipconfig and ping command.
Hand have a Windows PC. In dos window, Type ipconfig, the machine can check the "Set" or "automatically obtain" IP address. Figure:
Here are a few possibilities:
IP address and gateway address are correct. (There is no problem, you can enter the next step)
IP address is 0.0.0.0, or 169.254.255.x. (Did not get to IP, DHCP is a problem)
Incorrect IP address, such as: LAN segment is 192.168.1.x, but to get the IP address is 192.168.0.x. (Description have private access DHCP server, DHCP lead to conflict)
When broken network, it must first determine if there are problems within the network. Usually the ping network gateway can be judged. Figure:
The network packet loss rate should be 0, wired ping value generally within 1ms, wireless ping value between 1ms-20ms. If the ping packet loss or high value exists, then the problem is the internal network. It requires troubleshooting equipment problems within the network cable, loop switches. If the value of a normal wired ping, ping the wireless high values (50ms or more), it means that the wireless device has a problem (insufficient signal strength, the interference line, not AP performance reasons) .
After the network issue exclude, and then ping the public IP address, if nowhere, then the problem lies in the router gateway above. Below, 114.114.114.114 a common DNS server is, since the public Internet 114, higher than the value of ping network number, generally between 1ms-50ms.
114 value can ping and ping lossless normal, normal network stated otherwise abnormal external network, the router needs to troubleshoot problems and wan port line
If you can ping outside the network, but are still unable to get online, that is the general problem of the dns. It can be determined by ping the domain name.
The network will be the presence of virus, IP address conflicts. If you find Ip address is incorrect, ping instability within the network, we need to be considered within the network virus, network loops and other reasons.
2. external network problem diagnosis
If everything is normal within the network, then the problem probably appear on the external network line (cat-hardware) or router. The determination is more secure, the computer directly connected to the Internet in the light cat test, there is a possibility:
Optical network directly connected to the cat remains a problem, it can be confirmed that the reason the line. Daily operators can find direct repair.
Directly connected to the light speed cat normal, after a slow network router, then the problem lies in the router. Consider router hardware aging, inadequate performance, network cable connection is bad and so on.
3. A summary of some other network problems
There are some network problems occur from time to time, usually there is a possibility:
Router performance bottlenecks during peak network. View performance metrics to determine when a router is recommended for network peak.
Broadcast storms occur from time to time. You need to capture or use WFilter judge to see if there is a network storm.
Less than upload bandwidth when the network peak. For broadband uplink and downlink unequal, it is not enough upstream bandwidth is also a common cause of the malfunction. It can be determined by looking at the total upload bandwidth.
The best network management and technical personnel to prepare some common troubleshooting software, such as wireshark packet capture tools. Alternatively, the ping may be performed by detecting plug WFilter health of the network (or gateway WSG) automatically, arp, tracert detecting the like, so that a majority of the detected key network problems.
You can also view real-time bandwidth usage and so on.
