netstat
netstat provides useful information regarding traffic flow.
In particular, netstat -i lists statistics for each interface,
netstat -s provides a full listing of several counters,
and 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 /bin/kstat
command. Through Solaris 9, netstat -k provides a listing of
several component kstat statistics.
Here are some of the issues that can be revealed with netstat:
netstat -i: (Collis+Ierrs+Oerrs)/(Ipkts+Opkts)
> 2%: This may indicate a network hardware issue.
netstat -i: (Collis/Opkts) > 10%: The interface
is overloaded. Traffic will need to be reduced or redistributed to
other interfaces or servers.
netstat -i: (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
rsize and wsize mount 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.
