Use this command with the –m option to look at mbuf memory usage, which will tell you something about socket and network memory usage.

By default, the extended netstat statistics are turned off in /etc/ with the line:
/usr/sbin/no -o extendednetstats=0 >>/dev/null 2>&1
To enable these statistics, change to extendednetstats=1 and reboot. You can also try to set this directly with no. When using netstat -m, pipe to page because the first information is some of the most important:
67 mbufs in use:
64 mbuf cluster pages in use
272 Kbytes allocated to mbufs
0 requests for mbufs denied
0 calls to protocol drain routines
0 sockets not created because sockthresh was reached

-- At the end of the file:
Streams mblk statistic failures:
0 high priority mblk failures
0 medium priority mblk failures
0 low priority mblk failures

Use netstat -i <interval to collect data> to look at network usage and possible dropped packets.