netstat -in command

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This netstat function shows the state of all configured interfaces.

The following example shows the statistics for a workstation with an integrated Ethernet (en1), a PCI-X Gigabit Ethernet (en0) and Fibre Channel Adapter configured for TCP/IP (fc0): 
# netstat -in
Name  Mtu   Network     Address              Ipkts Ierrs    Opkts Oerrs  Coll
en1   1500  link#2      0.9.6b.3e.0.55       28800     0      506     0     0
en1   1500  10.3.104    10.3.104.116         28800     0      506     0     0
fc0   65280 link#3      0.0.c9.33.17.46         12     0       11     0     0
fc0   65280 192.6.0     192.6.0.1               12     0       11     0     0
en0   1500  link#4      0.2.55.6a.a5.dc         14     0       20     5     0
en0   1500  192.1.6     192.1.6.1               14     0       20     5     0
lo0   16896 link#1                           33339     0    33343     0     0
lo0   16896 127         127.0.0.1            33339     0    33343     0     0

The count values are summarized since system startup.

Name
Interface name.
Mtu
Maximum transmission unit. The maximum size of packets in bytes that are transmitted using the interface.
Ipkts
Total number of packets received.
Ierrs
Total number of input errors. For example, malformed packets, checksum errors, or insufficient buffer space in the device driver.
Opkts
Total number of packets transmitted.
Oerrs
Total number of output errors. For example, a fault in the local host connection or adapter output queue overrun.
Coll
Number of packet collisions detected.
Note: The netstat -i command does not support the collision count for Ethernet interfaces (see Adapter statistics for Ethernet statistics).

Following are some tuning guidelines:

  • If the number of errors during input packets is greater than 1 percent of the total number of input packets (from the command netstat -i); that is, 
    Ierrs > 0.01 x Ipkts

    Then run the netstat -m command to check for a lack of memory.

  • If the number of errors during output packets is greater than 1 percent of the total number of output packets (from the command netstat -i); that is, 
    Oerrs > 0.01 x Opkts
    Then increase the send queue size (xmt_que_size) for that interface. The size of the xmt_que_size could be checked with the following command: 
    # lsattr -El adapter
  • If the collision rate is greater than 10 percent, that is, 
    Coll / Opkts > 0.1

    Then there is a high network utilization, and a reorganization or partitioning may be necessary. Use the netstat -v or entstat command to determine the collision rate.