netstat provides useful information regarding traffic flow.
netstat -i lists statistics for each interface,
netstat -s provides a full listing of several counters,
netstat -rs provides routing table statistics.
netstat -an reports all open ports.
netstat -k provides a useful summary of several network-related
statistics up through Solaris 9, but this option was removed
in Solaris 10 in favor of the
command. Through Solaris 9,
netstat -k provides a listing of
Here are some of the issues that can be revealed with
(Collis+Ierrs+Oerrs)/(Ipkts+Opkts)> 2%: This may indicate a network hardware issue.
(Collis/Opkts)> 10%: The interface is overloaded. Traffic will need to be reduced or redistributed to other interfaces or servers.
(Ierrs/Ipkts)> 25%: Packets are probably being dropped by the host, indicating an overloaded network (and/or server). Retransmissions can be dropped by reducing the
wsizemount parameters to 2048 on the clients. Note that this is a temporary workaround, since this has the net effect of reducing maximum NFS throughput on the segment.
netstat -s: If significant numbers of packets arrive with bad headers, bad data length or bad checksums, check the network hardware.
netstat -i: If there are more than 120 collisions/second, the network is overloaded. See the suggestions above.
netstat -i: If the sum of input and output packets is higher than about 600 for a 10Mbs interface or 6000 for a 100Mbs interface, the network segment is too busy. See the suggestions above.
netstat -r: This form of the command provides the routing table. Make sure that the routes are as you expect them to be.