Practical TCP/IP and Ethernet Networking- P28: One of the great protocols that has been inherited from the Internet is TCP/IP and this is being used as the open standard today for all network and communications systems. The reasons for this popularity are not hard to find. | 252 Practical TCP IP and Ethernet Networking NETSTAT The command is usually typed in lower case letters only netstat . This reports the status of the network interfaces and ports. NETSTAT -i The command typed is netstat -i a space is inserted before the hyphen and the following letter all letters in lower case only . These statistics relate to running totals from when the system was last started. The total number of packets should be balanced between all network interfaces on the network. The output and input errors for each of the interfaces should be carefully examined. Output errors generally indicate hardware failures of the local system. If the output errors increase to about a quarter of the total packet output it is time to replace the hardware. Input errors are more difficult to analyze. These could result from any host on the network - this being caused by faulty network hardware network interface card cabling noise or the network device driver or an overloaded host. The collision statistic indicates the number of collisions and should be looked at as a percentage of the total number of packets transmitted and not as an absolute number. The queue statistic indicates when the network is so busy and thus congested that the Network interface has packets queued and waiting to be sent. It should be zero. NETSTAT The most important statistic here is the Send-Q which should be zero. A non-zero value indicates severe congestion. NETSTAT -nr The command is usually typed in lower case with a space before the hyphen and following letters netstat -nr . This gives information about the default gateway. This can be useful for troubleshooting why packets don t get to their destination. Ping This provides an indication of connectivity between hosts on a network or a series of interconnected networks and provides some measure of the time taken to traverse the internetworks the round-trip delay . In pinging a host if it times out this could mean that either there is no .
