Infinet Wireless: Technical Documentation
Page tree
Skip to end of metadata
Go to start of metadata

Successfully pass the free certification exam at IW Academy and become an Infinet Certified Engineer.

To the certification exam

Description

The "netstat" command allows to monitor network connections, network packets statistic for each protocol, to display routing tables and statistics for network interfaces.

Syntax:

net -r print routing table
net -i [clear] print interface table
net -s print IP statistics
net -s{rut} print protocol statistics (raw,udp,tcp)

Parameters

ParametersDescription

-r

Displays the content of the system routing tables.

Flags for specific routes have the following meaning:

  • "U" – this routing table element is currently active.
  • "H" – this route leads to a host. If this flag is not set, the route goes to a network.
  • "D" – this route has been created using the "icmp redirect" protocol.
  • "M" – this route has been modified using the "icmp redirect" protocol.
  • "G" – this route is connected to a host. If this flag is not set, it is considered that the route destination is directly connected.
  • "S" – it's a static route, set by the operator using a "route add" command.
  • "1" – a pseudostatic route, set as a result of a "rip static" command.
  • "L" – a route points to a directly connected host (for such a route an APR request may be performed).
  • "C" – when using this route, more specific routes may be created (e.g. using the "L" flag).

-i [clear]

Displays an information about each network interface in the system.

  • "clear" – resets a statistic of inbound / outbound packets and errors.
-s{rut}

Displays statistics for IP and ICMP packets.

  • "r" – if added, statistic of RAW protocol packets is displayed.
  • "u" – statistic of UDP protocol packets is displayed.
  • "t" – statistic of TCP protocol packets is displayed.

Examples

Display the content of the system routing tables using the "-r" parameter.

Routing tables
Destination        Gateway            Flags     Refs     Use  Interface
default            192.168.103.1      UGS         1       47  svi1
10.10.10.0/24      link#2             UC          0        0  eth0
127.0.0.1          127.0.0.1          UH          2       26  lo0
192.168.103.0/24   link#6             UC          0        0  svi1
192.168.103.1      6c:3b:e5:51:e3:8d  UHL         1        0  svi1
192.168.103.20     bc:ee:7b:8d:32:65  UHL         0     1743  svi1
192.168.103.243    08:00:27:54:47:bf  UHL         1    17257  svi1
224.0.0.0/8        127.0.0.1          UGS         0        0  lo0

Reset the statistic of packets and display the information about network interfaces using the "netstat -i [clear]" command.

Name      Network            Address               Ipkts Ierrs      Opkts Oerrs
lo0       Link:                                        0     0          0     0
lo0       127.0.0.1/32       127.0.0.1
eth0      Link:              00043503f7dd              0     0          0     0
eth0      10.10.10.0/24      10.10.10.14
eth1      Link:              00043513f7dd              0     0          0     0
eth1      none               none
rf5.0     Link:              00043523f7dd              0     0          0     0
rf5.0     none               none
null0*    Link:                                        0     0          0     0
svi1      Link:              02043503f7dd              0     0          0     0
svi1      192.168.103.0/24   192.168.103.37

Use the "-s" parameter to display packet statistic.

IP statistic:
ips_total           8584161 (total packets received)
ips_badsum                0 (checksum bad)
ips_tooshort              0 (packet too short)
ips_toosmall              0 (not enough data)
ips_badhlen               0 (ip header length < data size)
ips_badlen                0 (ip length < ip header length)
ips_fragments             0 (fragments received)
ips_fragdropped           0 (frags dropped (dups,ipstat. out of space))
ips_fragtimeout           0 (fragments timed out)
ips_forward               0 (packets forwarded)
ips_cantforward     2496172 (packets rcvd for unreachable dest)
ips_redirectsent          0 (packets forwarded on same net)
ips_noproto               0 (unknown or unsupported protocol)
ips_delivered       6087989 (datagrams delivered to upper level
ips_localout         335787 (total ip packets generated here)
ips_odropped              0 (lost packets due to nobufs,ipstat. etc.)
ips_reassembled           0 (total packets reassembled ok)
ips_fragmented            0 (datagrams sucessfully fragmented)
ips_ofragments            0 (output fragments created)
ips_cantfrag              0 (don't fragment flag was set,ipstat. etc.)
ips_badoptions            0 (error in option processing)
ips_noroute               0 (packets discarded due to no route)
ips_badvers               0 (ip version != 4)
ips_rawout            17401 (total raw ip packets generated)
ips_badfrags              0 (malformed fragments (bad length))
ips_rcvmemdrop            0 (frags dropped for lack of memory)
ips_toolong               0 (ip length > max ip packet size)

ICMP Staticstic:
icps_error                0 ( # of calls to icmp_error )
icps_oldshort             0 ( no error 'cuz old ip too short )
icps_oldicmp              0 ( no error 'cuz old was icmp )
icps_badcode              0 ( icmp_code out of range )
icps_tooshort             0 ( packet < ICMP_MINLEN )
icps_checksum             0 ( bad checksum )
icps_badlen               0 ( calculated bound mismatch )
icps_reflect              0 ( number of responses )
icps_bmcastecho           0 ( rejected broadcast icmps )

Display statistic of UDP protocol packets using the "netstat -su" command.

UDP statistic:
udps_ipackets       5878277
udps_opackets         11019
udps_hdrops               0
udps_badsum               0
udps_badlen               0
udps_noport               0
udps_fullsock             0
udps_pcbhashmiss      17511
0.0.0.0:0 snmp
0.0.0.0:161 snmp
0.0.0.0:22534 trap