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How to Display the Status of Transport Protocols
You can display the status of the transport protocols through the netstat command. For detailed information, refer to the netstat(1M) man page.
Display the status of the TCP and SCTP transport protocols on a system.
$ netstat
Display the status of a particular transport protocol on a system.
$ netstat -P transport-protocol
Values for the transport-protocol variable are tcp, sctp, or udp.
Example 8-6 Displaying the Status of the TCP and SCTP Transport Protocols
This example shows the output of the basic netstat command. Note that IPv4-only information is displayed.
$ netstat TCP: IPv4 Local Address Remote Address Swind Send-Q Rwind Recv-Q State ----------------- -------------------- ----- ------ ----- ------ ------- lhost-1.login abc.def.local.Sun.COM.980 49640 0 49640 0 ESTABLISHED lhost-1.login ghi.jkl.local.Sun.COM.1020 49640 1 49640 0 ESTABLISHED remhost-1.1014 mno.pqr.remote.Sun.COM.nfsd 49640 0 49640 0 TIME_WAIT SCTP: Local Address Remote Address Swind Send-Q Rwind Recv-Q StrsI/O State ---------------- -------------- ----- ------ ------ ------ ------ ------- *.echo 0.0.0.0 0 0 102400 0 128/1 LISTEN *.discard 0.0.0.0 0 0 102400 0 128/1 LISTEN *.9001 0.0.0.0 0 0 102400 0 128/1 LISTEN |
Example 8-7 Displaying the Status of a Particular Transport Protocol
This example shows the results when you specify the -P option of netstat.
$ netstat -P tcp TCP: IPv4 Local Address Remote Address Swind Send-Q Rwind Recv-Q State ----------------- -------------------- ----- ------ ----- ------ ------- lhost-1.login abc.def.local.Sun.COM.980 49640 0 49640 0 ESTABLISHED lhost.login ghi.jkl.local.Sun.COM.1020 49640 1 49640 0 ESTABLISHED remhost.1014 mno.pqr.remote.Sun.COM.nfsd 49640 0 49640 0 TIME_WAIT TCP: IPv6 Local Address Remote Address Swind Send-Q Rwind Recv-Q State If ---------------- ---------------------- ------ ----- ------ ----------- ----- localhost.38983 localhost.32777 49152 0 49152 0 ESTABLISHED localhost.32777 localhost.38983 49152 0 49152 0 ESTABLISHED localhost.38986 localhost.38980 49152 0 49152 0 ESTABLISHED |
How to Display Network Interface Status
The i option of the netstat command shows the state of the network interfaces that are configured on the local system. With this option, you can determine the number of packets a system transmits and receives on each network.
Example 8-8 Network Interface Status Display
The next example shows the status of IPv4 and IPv6 packet flow through the host's interfaces.
For example, the input packet count (Ipkts) that is displayed for a server can increase each time a client tries to boot, while the output packet count (Opkts) remains steady. This outcome suggests that the server is seeing the boot request packets from the client. However, the server does not know to respond to them. This confusion might be caused by an incorrect address in the hosts, or ethers database.
However, if the input packet count is steady over time, then the machine does not see the packets at all. This outcome suggests a different type of failure, possibly a hardware problem.
Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis Queue lo0 8232 loopback localhost 142 0 142 0 0 0 hme0 1500 host58 host58 1106302 0 52419 0 0 0 Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis lo0 8252 localhost localhost 142 0 142 0 0 hme0 1500 fe80::a00:20ff:feb9:4c54/10 fe80::a00:20ff:feb9:4c54 1106305 0 52422 0 0 |
How to Display the Status of Sockets
The -a option of the netstat command enables you to view the status of sockets on the local host.
Type the following to display the status of sockets and routing table entries:
You can use your user account to run this option of netstat.
% netstat -a
Example 8-9 Displaying All Sockets and Routing Table Entries
The output of the netstat -a command shows extensive statistics. The following example shows portions of typical netstat -a output.
UDP: IPv4
Local Address Remote Address State
-------------------- -------------------- -------
*.bootpc Idle
host85.bootpc Idle
*.* Unbound
*.* Unbound
*.sunrpc Idle
*.* Unbound
*.32771 Idle
*.sunrpc Idle
*.* Unbound
*.32775 Idle
*.time Idle
.
.
*.daytime Idle
*.echo Idle
*.discard Idle
UDP: IPv6
Local Address Remote Address State If
--------------------------------- --------------------------------- ---------- -----
*.* Unbound
*.* Unbound
*.sunrpc Idle
*.* Unbound
*.32771 Idle
*.32778 Idle
*.syslog Idle
.
.
TCP: IPv4
Local Address Remote Address Swind Send-Q Rwind Recv-Q State
-------------------- -------------------- ----- ------ ----- ------ -------
*.* *.* 0 0 49152 0 IDLE
localhost.4999 *.* 0 0 49152 0 LISTEN
*.sunrpc *.* 0 0 49152 0 LISTEN
*.* *.* 0 0 49152 0 IDLE
*.sunrpc *.* 0 0 49152 0 LISTEN
.
.
*.printer *.* 0 0 49152 0 LISTEN
*.time *.* 0 0 49152 0 LISTEN
*.daytime *.* 0 0 49152 0 LISTEN
*.echo *.* 0 0 49152 0 LISTEN
*.discard *.* 0 0 49152 0 LISTEN
*.chargen *.* 0 0 49152 0 LISTEN
*.shell *.* 0 0 49152 0 LISTEN
*.shell *.* 0 0 49152 0 LISTEN
*.kshell *.* 0 0 49152 0 LISTEN
*.login
.
.
*.* 0 0 49152 0 LISTEN
*TCP: IPv6
Local Address Remote Address Swind Send-Q Rwind Recv-Q State If
----------------------- ----------------------- ----- ------ ----- ------ ----
*.* *.* 0 0 49152 0 IDLE
*.sunrpc *.* 0 0 49152 0 LISTEN
*.* *.* 0 0 49152 0 IDLE
*.32774 *.* 0 0 49152
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