Rack of Ethernet switches.

How To Read  netstat -a  Output

Use netstat -a to Display Network Status

The netstat command can describe all current network activity, listing active connections and listening services. The format of the netstat output varies from one operating system to the next. But netstat output has some common characteristics across operating systems. let's see how to read some example output.

TCP is a connection-oriented stateful protocol. Establishing and shutting down those connections requires 3-way handshakes, building up and tearing down each connection by transitioning through multiple states. A TCP service might be described as LISTENING when a server process is ready to begin establishing a connection on that port. That same port might be in other states as the initial 3-way handshake establishes the connection, ESTABLISHED when it is up and running, and in still other states as a 3-way handshake cleanly shuts down the connection. Uncooperative clients and servers may lead to other states as connections are cancelled or abandoned prematurely. The TCP states are:

CLOSED — Nothing is happening. At the server end, it has not yet started listening, or at the client end, the connection not yet started or has already been completely shut down.

LISTEN — A server transitions into this state without sending any packets.

SYN_SENT and SYN_RCVD — The three-way handshake to establish a connection has started but not yet completed.

ESTABLISHED — The opening 3-way handshake is complete and data streams can flow in both directions.

CLOSE_WAIT, LAST_ACK, FIN_WAIT_1, FIN_WAIT_2, CLOSING and TIME_WAIT — States used to cancel an incomplete connection or to cleanly shut down a established connection, with or without the full cooperation of the other end.

UDP is a datagram protocol in which individual datagrams or messages might be used to stream data but don't build stateful connections.

However, some implementations may show ESTABLISHED for UDP when a stateful application like a DNS resolver has sent a query but not yet received the corresponding reply.

The order of the sections of the report vary from one operating system to another. For the versions shown on this page, they are:

Linux 3.5.3 kernel

  • TCP, IPv4 and IPv6 mixed together
  • UDP, IPv4 and IPv6 mixed together
  • RAW IP: ICMP, IPv6-ICMP or ICMPv6, etc.

Linux 2.6.33 kernel

  • TCP, IPv4 and IPv6 mixed together
  • UDP, IPv4 and IPv6 mixed together
  • RAW IP: ICMP, IPv6-ICMP or ICMPv6, etc.

OpenBSD 5.6 kernel

  • RAW IP
  • TCP over IPv4
  • UDP over IPv4
  • TCP over IPv6
  • UDP over IPv6

OpenBSD 5.0 kernel

  • RAW IP
  • TCP over IPv4
  • UDP over IPv4
  • TCP over IPv6
  • UDP over IPv6

OpenBSD 4.5 kernel

  • TCP over IPv4
  • UDP over IPv4
  • TCP over IPv6
  • UDP over IPv6

SunOS 5.10 kernel

Linux describes the endpoints as host:port where host is resolved to a fully qualified domain name and then truncated to 20 characters max, left as an IP address if the -n option was used or the hostname does not resolve, and designated as * for services listening on all IPv4 interfaces. The port is replaced with the corresponding entry from /etc/services is there is one, left numeric if the -n option was used or their is no entry in the services file.

OpenBSD and Solaris both use "." rather than ":" to separate the host and port. Machines in the same domain are described by hostname only.

Cisco IOS uses a completely different format.

Linux

Linux 3.5.3 kernel

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 *:8880                      *:*                         LISTEN
tcp        0      0 *:8881                      *:*                         LISTEN
tcp        0      0 *:8882                      *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:7634      *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:domain    *:*                         LISTEN
tcp        0      0 c-98-223-97-179.hsd1:domain *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:domain    *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 *:ipp                       *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:31416     *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:953       *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:smtp      *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:9050      *:*                         LISTEN
tcp        0      0 *:30020                     *:*                         LISTEN
tcp        0      0 *:swat                      *:*                         LISTEN
tcp        0      0 *:smux                      *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:10026     *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:11211     *:*                         LISTEN
tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0      0 c-98-223-97-179.hsd1.:59410 a184-85-95-144.deploy.a:www ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:57351 ord08s06-in-f1.1e100.:https ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:54387 bbc-vip016.cwwtf.bbc.co:www TIME_WAIT
tcp        1      0 c-98-223-97-179.hsd1.:56500 einstein-dl.aei.uni-han:www CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:36249 72.21.207.146:www           ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:54384 bbc-vip016.cwwtf.bbc.co:www TIME_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:36250 72.21.207.146:www           TIME_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:54437 ord08s06-in-f2.1e100.:https ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:57037 75-146-106-233-Illinnoi:www ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:36247 72.21.207.146:www           ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:37277 ord08s06-in-f15.1e100:https ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:36882 milkyway2.phys.rpi.edu:www  CLOSE_WAIT
tcp        1      0 c-98-223-97-179.hsd1.:57149 einstein-abp1.aei.uni-h:www CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:36241 72.21.207.146:www           ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:57038 75-146-106-233-Illinnoi:www ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:36246 72.21.207.146:www           ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:59431 a184-85-95-144.deploy.a:www ESTABLISHED
tcp        0      0 gateway.kc9rg.org:52222        laptop.kc9rg.org:ssh     ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:35057 192.33.217.12:www           CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:50697 www-slb-10-08-prn1.fa:https ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:41641 einstein.phys.uwm.edu:www   CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:57035 75-146-106-233-Illinnoi:www ESTABLISHED
tcp        0    336 gateway.kc9rg.org:52356        laptop.kc9rg.org:ssh     ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:57033 75-146-106-233-Illinnoi:www ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:36435 176.32.96.45:www            ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:41640 einstein.phys.uwm.edu:www   CLOSE_WAIT
tcp        1      0 c-98-223-97-179.hsd1.:60294 192.33.217.12:www           CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:38905 r-199-59-148-9.twttr.co:www ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:35056 192.33.217.12:www           CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:36248 72.21.207.146:www           TIME_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:58867 a23-62-97-88.deploy.aka:www ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:41311 ord08s06-in-f25.1e100:https ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:36395 176.32.96.45:www            ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:57150 einstein-abp1.aei.uni-h:www CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:57034 75-146-106-233-Illinnoi:www ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:56501 einstein-dl.aei.uni-han:www CLOSE_WAIT
tcp        1      0 c-98-223-97-179.hsd1.:57659 orbit.psi.edu:www           CLOSE_WAIT
tcp        1      0 c-98-223-97-179.hsd1.:60295 192.33.217.12:www           CLOSE_WAIT
tcp        0      0 c-98-223-97-179.hsd1.:50711 ord08s06-in-f12.1e100:https ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:57036 75-146-106-233-Illinnoi:www ESTABLISHED
tcp        0      0 c-98-223-97-179.hsd1.:40840 den03s05-in-f20.1e100:https ESTABLISHED
tcp        1      0 c-98-223-97-179.hsd1.:35055 192.33.217.12:www           CLOSE_WAIT
tcp        1      0 c-98-223-97-179.hsd1.:60296 192.33.217.12:www           CLOSE_WAIT
tcp        0      0 *:domain                    *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 *:ipp                       *:*                         LISTEN
tcp        0      0 *:sunrpc                    *:*                         LISTEN
udp        0      0 gateway.kc9rg.org:domain    *:*
udp        0      0 c-98-223-97-179.:domain     *:*
udp        0      0 gateway.kc9rg.org:domain    *:*
udp        0      0 *:bootps                    *:*
udp        0      0 *:bootpc                    *:*
udp        0      0 *:bootpc                    *:*
udp        0      0 *:sunrpc                    *:*
udp        0      0 gateway.kc9rg.org:ntp       *:*
udp        0      0 c-98-223-97-179.hsd:ntp     *:*
udp        0      0 gateway.kc9rg.org:ntp       *:*
udp        0      0 *:ntp                       *:*
udp        0      0 *:snmp                      *:*
udp        0      0 *:49548                     *:*
udp        0      0 gateway.kc9rg.org:isakmp    *:*
udp        0      0 c-98-223-97-179.:isakmp     *:*
udp        0      0 gateway.kc9rg.org:isakmp    *:*
udp        0      0 *:ipp                       *:*
udp        0      0 *:743                       *:*
udp        0      0 *:25629                     *:*
udp        0      0 *:5957                      *:*
udp        0      0 *:1900                      *:*
udp        0      0 *:2524                      *:*
udp        0      0 gateway.kc9rg.org:11211     *:*
udp        0      0 *:domain                    *:*
udp        0      0 *:sunrpc                    *:*
udp        0      0 ::1:ntp                     *:*
udp        0      0 2001:1800:1234:90::1:ntp    *:*
udp        0      0 fe80::211:95ff:fe1e:ntp     *:*
udp        0      0 fe80::6e62:6dff:feb:ntp     *:*
udp        0      0 gateway.kc9rg.org:ntp       *:*
udp        0      0 *:ntp                       *:*
udp        0      0 fe80::6e62:6dff::isakmp     *:*
udp        0      0 gateway.kc9rg.org:isakmp    *:*
udp        0      0 2001:1800:1234:90::1:isakmp *:*
udp        0      0 fe80::211:95ff:f:isakmp     *:*
udp        0      0 ::1:isakmp                  *:*
udp        0      0 *:743                       *:*
udp        0      0 *:41839                     *:*
udp        0      0 *:58258                     *:*
udp        0      0 *:27822                     *:*
raw        0      0 *:icmp                      *:*                         7
raw        0      0 *:ipv6-icmp                 *:*                         7

Linux 2.6.33 kernel

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address             State
tcp        0      0 *:8882                      *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:7634      *:*                         LISTEN
tcp        0      0 *:5555                      *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:domain    *:*                         LISTEN
tcp        0      0 c-98-223-99-119.hsd1:domain *:*                         LISTEN
tcp        0      0 gateway.local:domain        *:*                         LISTEN
tcp        0      0 gateway.local:domain        *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:domain    *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 *:ipp                       *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:31416     *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:953       *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:smtp      *:*                         LISTEN
tcp        0      0 *:55707                     *:*                         LISTEN
tcp        0      0 *:30020                     *:*                         LISTEN
tcp        0      0 *:swat                      *:*                         LISTEN
tcp        0      0 *:902                       *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:10026     *:*                         LISTEN
tcp        0      0 gateway.kc9rg.org:11211     *:*                         LISTEN
tcp        0      0 *:sunrpc                    *:*                         LISTEN
tcp        0      0 *:8880                      *:*                         LISTEN
tcp        0      0 *:8881                      *:*                         LISTEN
tcp        1      0 c-98-223-99-119.hsd1.:45515 einstein-abp1.aei.uni-h:www CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:33758 einstein.phys.uwm.edu:www   CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:57521     laptop.kc9rg.org:ssh        ESTABLISHED
tcp        1      0 c-98-223-99-119.hsd1.:34713 192.33.217.12:www           CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:33389 einstein-dl.aei.uni-han:www CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:50012 fcds316.ord.llnw.net:www    CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43038     TIME_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:34723 192.33.217.12:www           CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:45514 einstein-abp1.aei.uni-h:www CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:40716 fcds93.ord.llnw.net:www     CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:33390 einstein-dl.aei.uni-han:www CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43039     TIME_WAIT
tcp        0      0 gateway.kc9rg.org:57528     laptop.kc9rg.org:ssh        ESTABLISHED
tcp        0      0 gateway.kc9rg.org:ssh       laptop.kc9rg.org:25149      ESTABLISHED
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43037     TIME_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43045     TIME_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43044     TIME_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43043     TIME_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:45623 orbit.psi.edu:www           CLOSE_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:52057 192.33.217.12:www           CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43047     TIME_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43048     TIME_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:40177 cbf02m01-in-f103.1e100.:www CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43046     TIME_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:56508 milkyway2.phys.rpi.edu:www  CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43040     TIME_WAIT
tcp        0      0 c-98-223-99-119.hsd1.:43540 a96-17-76-73.deploy.aka:www ESTABLISHED
tcp        0      0 c-98-223-99-119.hsd1.:53875 acubed1.ecn.purdue.edu:ssh  ESTABLISHED
tcp        0      0 c-98-223-99-119.hsd1.:59935 cbf02m01-in-f106.1e100.:www ESTABLISHED
tcp        1      0 c-98-223-99-119.hsd1.:42911 einstein.phys.uwm.edu:www   CLOSE_WAIT
tcp        0      0 gateway.kc9rg.org:7634      gateway.kc9rg.org:43041     TIME_WAIT
tcp        1      0 c-98-223-99-119.hsd1.:50013 fcds316.ord.llnw.net:www    CLOSE_WAIT
tcp        0      0 c-98-223-99-119.hsd1.:47562 channel-hs-12-01-snc7:https ESTABLISHED
tcp        0      0 c-98-223-99-119.hsd1.:50454 bbc-vip112.telhc.bbc.co:www ESTABLISHED
tcp        0      0 *:domain                    *:*                         LISTEN
tcp        0      0 *:ssh                       *:*                         LISTEN
tcp        0      0 *:ipp                       *:*                         LISTEN
tcp        0      0 *:microsoft-ds              *:*                         LISTEN
tcp        0      0 *:netbios-ssn               *:*                         LISTEN
tcp        0      0 *:sunrpc                    *:*                         LISTEN
udp        0      0 *:mdns                      *:*
udp        0      0 *:42355                     *:*
udp        0      0 *:1900                      *:*
udp        0      0 *:1900                      *:*
udp        0      0 *:39524                     *:*
udp        0      0 gateway.kc9rg.org:11211     *:*
udp        0      0 *:60372                     *:*
udp        0      0 c-98-223-99-119.h:64656     ns1.thdo.bbc.co.uk:domain   ESTABLISHED
udp        0      0 gateway.kc9rg.org:domain    *:*
udp        0      0 c-98-223-99-119.:domain     *:*
udp        0      0 gateway.local:domain        *:*
udp        0      0 gateway.local:domain        *:*
udp        0      0 gateway.kc9rg.org:domain    *:*
udp        0      0 *:bootps                    *:*
udp        0      0 *:bootpc                    *:*
udp        0      0 gateway.local:ntp           *:*
udp        0      0 gateway.local:ntp           *:*
udp        0      0 gateway.kc9rg.org:ntp       *:*
udp        0      0 c-98-223-99-119.hsd:ntp     *:*
udp        0      0 gateway.kc9rg.org:ntp       *:*
udp        0      0 *:ntp                       *:*
udp        0      0 10.1.1.255:netbios-ns       *:*
udp        0      0 gateway.kc9rg.org:netbios-ns *:*
udp        0      0 *:netbios-ns                *:*
udp        0      0 10.1.1.255:netbios-dgm      *:*
udp        0      0 gateway.kc9rg.org:netbios-dgm *:*
udp        0      0 *:netbios-dgm               *:*
udp        0      0 gateway.local:isakmp        *:*
udp        0      0 gateway.local:isakmp        *:*
udp        0      0 gateway.kc9rg.org:isakmp    *:*
udp        0      0 c-98-223-99-119.:isakmp     *:*
udp        0      0 gateway.kc9rg.org:isakmp    *:*
udp        0      0 *:608                       *:*
udp        0      0 *:ipp                       *:*
udp        0      0 *:domain                    *:*
udp        0      0 *:sunrpc                    *:*
udp        0      0 fe80::6e62:6dff:feb:ntp     *:*
udp        0      0 fe80::211:95ff:fe1e:ntp     *:*
udp        0      0 fe80::250:56ff:fec0:1:ntp   *:*
udp        0      0 gateway.kc9rg.org:ntp       *:*
udp        0      0 ::1:ntp                     *:*
udp        0      0 fe80::250:56ff:fec0:8:ntp   *:*
udp        0      0 *:ntp                       *:*
udp        0      0 fe80::250:56ff:f:isakmp     *:*
udp        0      0 fe80::250:56ff:f:isakmp     *:*
udp        0      0 fe80::6e62:6dff::isakmp     *:*
udp        0      0 gateway.kc9rg.org:isakmp    *:*
udp        0      0 fe80::211:95ff:f:isakmp     *:*
udp        0      0 ::1:isakmp                  *:*
udp        0      0 *:608                       *:*
raw        0      0 *:icmp                      *:*                         7
raw        0      0 *:icmp                      *:*                         7
raw        0      0 *:ipv6-icmp                 *:*                         7

OpenBSD

OpenBSD 5.6

Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
ip           0      0  *.*                    *.*                    17
ip           0      0  *.*                    *.*                    17
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp          0      0  192.168.6.41.25554     199.96.57.6.https      CLOSE_WAIT
tcp         27      0  192.168.6.41.24632     a23-202-194-110..https CLOSE_WAIT
tcp        414      0  192.168.6.41.34495     a23-62-6-66.depl.www   CLOSE_WAIT
tcp          0      0  192.168.6.41.30726     a184-25-157-41.d.www   ESTABLISHED
tcp         53      0  192.168.6.41.12300     a23-218-85-183.d.https CLOSE_WAIT
tcp          0      0  192.168.6.41.33073     108.162.232.198.www    CLOSE_WAIT
tcp          0      0  192.168.6.41.30572     ad-dc6.mediaplex.https CLOSE_WAIT
tcp          0      0  192.168.6.41.31832     72.21.202.62.www       CLOSE_WAIT
tcp         53      0  192.168.6.41.44813     a23-218-99-86.de.https CLOSE_WAIT
tcp         31      0  192.168.6.41.31562     72.21.91.187.https     CLOSE_WAIT
tcp          0      0  192.168.6.41.4606      ec2-54-243-68-84.www   CLOSE_WAIT
tcp          0      0  192.168.6.41.12475     https-208-111-13.https CLOSE_WAIT
tcp          0      0  192.168.6.41.35883     lga15s46-in-f9.1.www   CLOSE_WAIT
tcp         76      0  192.168.6.41.38519     edge-star-shv-17.https CLOSE_WAIT
tcp         31      0  192.168.6.41.2819      199.16.156.201.https   CLOSE_WAIT
tcp          0      0  192.168.6.41.5945      a23-62-6-40.depl.www   ESTABLISHED
tcp          0      0  192.168.6.41.1825      176.32.96.130.www      ESTABLISHED
tcp          0      0  192.168.6.41.13152     176.32.96.130.www      ESTABLISHED
tcp          0      0  192.168.6.41.9956      198.41.209.137.https   CLOSE_WAIT
tcp          0      0  192.168.6.41.1748      72.21.202.62.www       CLOSE_WAIT
tcp          0      0  192.168.6.41.9524      72.21.202.62.www       CLOSE_WAIT
tcp         53      0  192.168.6.41.19285     a23-218-98-93.de.https CLOSE_WAIT
tcp          0      0  192.168.6.41.1332      a23-218-90-18.de.www   CLOSE_WAIT
tcp          0      0  192.168.6.41.33941     a23-218-90-18.de.www   ESTABLISHED
tcp          0      0  192.168.6.41.28370     a23-218-98-93.de.www   ESTABLISHED
tcp          0      0  *.6000                 *.*                    LISTEN
tcp          0      0  localhost.smtp         *.*                    LISTEN
tcp          0      0  *.ssh                  *.*                    LISTEN
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
udp          0      0  192.168.6.41.42338     jikan.ae7.st.ntp      
udp          0      0  192.168.6.41.40101     titan.alltraders.ntp  
udp          0      0  192.168.6.41.28175     paladin.latt.net.ntp  
udp          0      0  192.168.6.41.25169     a1.pcloud.com.ntp     
udp          0      0  *.syslog               *.*                   
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp6         0      0  *.6000                 *.*                    LISTEN
tcp6         0      0  localhost.smtp         *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.smtp       *.*                    LISTEN
tcp6         0      0  *.ssh                  *.*                    LISTEN

OpenBSD 5.0

Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
ip           0      0  *.*                    *.*                    17
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp          0      0  laptop.29923           gateway.ssh            TIME_WAIT
tcp          0      0  laptop.20800           75-146-106-233-I.ssh   TIME_WAIT
tcp          0      0  laptop.16678           gateway.ssh            TIME_WAIT
tcp          0      0  laptop.25300           75-146-106-233-I.ssh   TIME_WAIT
tcp          0      0  laptop.12771           gateway.ssh            ESTABLISHED
tcp          0      0  localhost.6011         localhost.1936         ESTABLISHED
tcp          0      0  localhost.1936         localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         localhost.32627        ESTABLISHED
tcp          0      0  localhost.32627        localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         localhost.13826        ESTABLISHED
tcp          0      0  localhost.13826        localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         localhost.39131        ESTABLISHED
tcp          0      0  localhost.39131        localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         localhost.2183         ESTABLISHED
tcp          0      0  localhost.2183         localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         localhost.33599        ESTABLISHED
tcp          0      0  localhost.33599        localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         localhost.29820        ESTABLISHED
tcp          0      0  localhost.29820        localhost.6011         ESTABLISHED
tcp          0      0  localhost.6011         *.*                    LISTEN
tcp          0      0  laptop.ssh             gateway.57528          ESTABLISHED
tcp          0      0  localhost.6010         localhost.12450        ESTABLISHED
tcp          0      0  localhost.12450        localhost.6010         ESTABLISHED
tcp          0      0  localhost.6010         *.*                    LISTEN
tcp          0      0  laptop.ssh             gateway.57521          ESTABLISHED
tcp          0      0  *.6000                 *.*                    LISTEN
tcp          0      0  *.time                 *.*                    LISTEN
tcp          0      0  *.daytime              *.*                    LISTEN
tcp          0      0  *.auth                 *.*                    LISTEN
tcp          0      0  *.www                  *.*                    LISTEN
tcp          0      0  localhost.8000         *.*                    LISTEN
tcp          0      0  localhost.8001         *.*                    LISTEN
tcp          0      0  localhost.8002         *.*                    LISTEN
tcp          0      0  localhost.submissi     *.*                    LISTEN
tcp          0      0  localhost.smtp         *.*                    LISTEN
tcp          0      0  *.ssh                  *.*                    LISTEN
tcp          0      0  *.734[status]          *.*                    LISTEN
tcp          0      0  *.748[nlockmgr]        *.*                    LISTEN
tcp          0      0  *.938[ypserv]          *.*                    LISTEN
tcp          0      0  localhost.sunrpc       *.*                    LISTEN
tcp          0      0  *.sunrpc               *.*                    LISTEN
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
udp          0      0  localhost.biff         *.*
udp          0      0  *.who                  *.*
udp          0      0  *.807[status]          *.*
udp          0      0  *.919[nlockmgr]        *.*
udp          0      0  *.655[ypserv]          *.*
udp          0      0  localhost.sunrpc       *.*
udp          0      0  *.sunrpc               *.*
udp          0      0  *.syslog               *.*
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp6         0      0  localhost.6011         *.*                    LISTEN
tcp6         0      0  localhost.6010         *.*                    LISTEN
tcp6         0      0  *.6000                 *.*                    LISTEN
tcp6         0      0  *.time                 *.*                    LISTEN
tcp6         0      0  *.daytime              *.*                    LISTEN
tcp6         0      0  *.auth                 *.*                    LISTEN
tcp6         0      0  localhost.submissi     *.*                    LISTEN
tcp6         0      0  localhost.smtp         *.*                    LISTEN
tcp6         0      0  *.ssh                  *.*                    LISTEN
Active Internet connections (including servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        (state)
udp6         0      0  localhost.biff         *.*

OpenBSD 4.5

Active Internet connections (including servers)
Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp        0      0  localhost.6010         *.*                    LISTEN
tcp        0      0  www.ssh                c-98-223-99-119..46984 ESTABLISHED
tcp        0      0  www.www                conser10.lnk.tel.2328  ESTABLISHED
tcp        0      0  www.www                77-21-147-173-dy.64745 TIME_WAIT
tcp        0      0  www.www                hosted-by.leasew.33049 FIN_WAIT_2
tcp        0      0  www.www                lw43.wesee.com.8891    FIN_WAIT_2
tcp        0      0  www.www                dr-monroe.w3.org.42861 FIN_WAIT_2
tcp        0      0  www.www                host-85-201-86-1.49849 LAST_ACK
tcp        0      0  www.www                host5.wesee.com.18468  FIN_WAIT_2
tcp        0      0  www.www                pool-71-163-180-.57359 FIN_WAIT_1
tcp        0      0  www.www                2-227-14-161.ip1.52088 FIN_WAIT_2
tcp        0      0  www.www                s74-197-185-182..59812 FIN_WAIT_2
tcp        0      0  *.www                  *.*                    LISTEN
tcp        0      0  *.ssh                  *.*                    LISTEN
tcp        0      0  localhost.submissi     *.*                    LISTEN
tcp        0      0  localhost.smtp         *.*                    LISTEN
Active Internet connections (including servers)
Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)
udp        0      0  www.43386              173-203-122-111..ntp
udp        0      0  www.26888              lasvegas-nv-data.ntp
udp        0      0  www.31824              cheezum.mattnord.ntp
udp        0      0  *.syslog               *.*
Active Internet connections (including servers)
Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)
tcp6       0      0  localhost.6010         *.*                    LISTEN
tcp6       0      0  *.ssh                  *.*                    LISTEN
tcp6       0      0  localhost.submissi     *.*                    LISTEN
tcp6       0      0  localhost.smtp         *.*                    LISTEN

SunOS

SunOS 5.10

UDP: IPv4
   Local Address        Remote Address      State
-------------------- -------------------- ----------
      *.177                               Idle
localhost.domain                          Idle
rvl4.domain                               Idle
      *.utauthd-gm                        Idle
      *.sunrpc                            Idle
      *.*                                 Unbound
      *.32778                             Idle
      *.sunrpc                            Idle
      *.*                                 Unbound
      *.32782                             Idle
      *.*                                 Unbound
      *.*                                 Unbound
      *.*                                 Unbound
      *.32784                             Idle
      *.32785                             Idle
      *.*                                 Unbound
      *.32788                             Idle
      *.32789                             Idle
      *.1023                              Idle
      *.1022                              Idle
      *.1021                              Idle
      *.1020                              Idle
      *.32790                             Idle
      *.32791                             Idle
rvl4.40001           aibo.59723           Connected
      *.32792                             Idle
      *.32793                             Idle
      *.32794                             Idle
      *.lockd                             Idle
      *.lockd                             Idle
      *.32802                             Idle
      *.32804                             Idle
      *.32805                             Idle
      *.ntp                               Idle
localhost.ntp                             Idle
rvl4.ntp                                  Idle
      *.bootpc                            Idle
      *.546                               Idle
      *.32816                             Idle
      *.32817                             Idle
      *.32818                             Idle
      *.32819                             Idle
      *.32820                             Idle
      *.32821                             Idle
      *.biff                              Idle
      *.32822                             Idle
      *.32823                             Idle
      *.acmaint3_transd                      Idle
      *.netbios-ns                        Idle
      *.32825                             Idle
      *.32826                             Idle
      *.nfsd                              Idle
      *.nfsd                              Idle
      *.syslog                            Idle
      *.syslog                            Idle
      *.who                               Idle
localhost.32874      localhost.syslog     Connected
      *.netbios-dgm                       Idle
rvl4.netbios-ns                           Idle
      *.netbios-ns                        Idle
rvl4.netbios-dgm                          Idle
      *.netbios-dgm                       Idle

UDP: IPv6
   Local Address                     Remote Address                   State      If
--------------------------------- --------------------------------- ---------- -----
      *.177                                                         Idle
      *.sunrpc                                                      Idle
      *.*                                                           Unbound
      *.32778                                                       Idle
      *.*                                                           Unbound
      *.32784                                                       Idle
      *.*                                                           Unbound
      *.32788                                                       Idle
      *.1022                                                        Idle
      *.1020                                                        Idle
      *.32790                                                       Idle
      *.32791                                                       Idle
      *.32794                                                       Idle
      *.lockd                                                       Idle
      *.32802                                                       Idle
      *.32804                                                       Idle
      *.546                                                         Idle
      *.32817                                                       Idle
      *.32819                                                       Idle
      *.32821                                                       Idle
      *.32823                                                       Idle
      *.32825                                                       Idle
      *.nfsd                                                        Idle
      *.syslog                                                      Idle

TCP: IPv4
   Local Address        Remote Address    Swind Send-Q Rwind Recv-Q    State
-------------------- -------------------- ----- ------ ----- ------ -----------
rvl4.ssh             c-98-223-99-119.hsd1.in.comcast.net.38624 10240     79 49232      0 ESTABLISHED
      *.*                  *.*                0      0 49152      0 IDLE
localhost.6012             *.*                0      0 65535      0 LISTEN
      *.smtps              *.*                0      0 65535      0 LISTEN
      *.smtp               *.*                0      0 65535      0 LISTEN
      *.submission         *.*                0      0 65535      0 LISTEN
      *.32832              *.*                0      0 65535      0 LISTEN
      *.utdevmgrd          *.*                0      0 65535      0 LISTEN
      *.utsessiond         *.*                0      0 65535      0 LISTEN
rvl4.32838           rvl4.utdsd           36810      0 73620      0 ESTABLISHED
rvl4.utdsd           rvl4.32838           73620      0 73695      0 ESTABLISHED
localhost.domain           *.*                0      0 49152      0 LISTEN
      *.32840              *.*                0      0 65535      0 BOUND
rvl4.domain                *.*                0      0 49152      0 LISTEN
localhost.953              *.*                0      0 49152      0 LISTEN
      *.utauthd-cb         *.*                0      0 65535      0 LISTEN
      *.utauthd            *.*                0      0 65535      0 LISTEN
localhost.32842      localhost.utauthd-cb 36810      0 73620      0 ESTABLISHED
      *.1556               *.*                0      0 49152      0 LISTEN
localhost.utauthd-cb localhost.32842      73620      0 73662      0 ESTABLISHED
localhost.1557             *.*                0      0 49152      0 LISTEN
localhost.32769            *.*                0      0 49152      0 LISTEN
      *.sunrpc             *.*                0      0 49152      0 LISTEN
      *.*                  *.*                0      0 49152      0 IDLE
      *.sunrpc             *.*                0      0 49152      0 LISTEN
      *.*                  *.*                0      0 49152      0 IDLE
      *.32776              *.*                0      0 49152      0 LISTEN
      *.32777              *.*                0      0 49152      0 LISTEN
rvl4.ca_stat         templeton.nfsd       64128      0 1049800      0 ESTABLISHED
rvl4.utauthd         aibo.48818            8095      0 64240      0 ESTABLISHED
localhost.32850      localhost.utauthd-cb 36810      0 73620      0 ESTABLISHED
localhost.utauthd-cb localhost.32850      73620      0 73620      0 ESTABLISHED
      *.32778              *.*                0      0 49152      0 LISTEN
      *.32779              *.*                0      0 49152      0 LISTEN
      *.6002               *.*                0      0 65535      0 LISTEN
      *.1023               *.*                0      0 49152      0 BOUND
      *.6002               *.*                0      0 65535      0 LISTEN
      *.icd_db             *.*                0      0 49152      0 BOUND
      *.32780              *.*                0      0 49152      0 LISTEN
      *.32781              *.*                0      0 49152      0 LISTEN
rvl4.40001           rvl4.utsessiond      36810      0 73620      0 ESTABLISHED
rvl4.utsessiond      rvl4.40001           73620      0 73620      0 ESTABLISHED
      *.32782              *.*                0      0 49152      0 LISTEN
      *.32783              *.*                0      0 49152      0 LISTEN
rvl4.32855           rvl4.utsessiond      36810      0 73620      0 ESTABLISHED
rvl4.utsessiond      rvl4.32855           73620      0 73645      0 ESTABLISHED
      *.lockd              *.*                0      0 1049200      0 LISTEN
rvl4.utdevmgrd       aibo.53022            8095      0 64240      0 ESTABLISHED
      *.lockd              *.*                0      0 1048952      0 LISTEN
      *.32784              *.*                0      0 49152      0 LISTEN
      *.32785              *.*                0      0 49152      0 LISTEN
      *.32786              *.*                0      0 1049200      0 LISTEN
      *.32787              *.*                0      0 1048952      0 LISTEN
localhost.4999             *.*                0      0 49152      0 LISTEN
      *.32788              *.*                0      0 49152      0 LISTEN
      *.32789              *.*                0      0 49152      0 LISTEN
      *.fs                 *.*                0      0 49152      0 LISTEN
      *.32790              *.*                0      0 49152      0 LISTEN
      *.32791              *.*                0      0 49152      0 LISTEN
      *.32792              *.*                0      0 49152      0 LISTEN
      *.32793              *.*                0      0 49152      0 LISTEN
      *.32794              *.*                0      0 49152      0 LISTEN
      *.32795              *.*                0      0 49152      0 LISTEN
      *.32796              *.*                0      0 49152      0 LISTEN
      *.32797              *.*                0      0 49152      0 LISTEN
      *.finger             *.*                0      0 49152      0 LISTEN
      *.shell              *.*                0      0 49152      0 LISTEN
      *.omni               *.*                0      0 49152      0 LISTEN
      *.utrcmd             *.*                0      0 49152      0 LISTEN
      *.32798              *.*                0      0 49152      0 LISTEN
      *.32799              *.*                0      0 49152      0 LISTEN
      *.pop2               *.*                0      0 49152      0 LISTEN
      *.pop3               *.*                0      0 49152      0 LISTEN
      *.pop3s              *.*                0      0 49152      0 LISTEN
      *.imap               *.*                0      0 49152      0 LISTEN
      *.imaps              *.*                0      0 49152      0 LISTEN
      *.netbios-ssn        *.*                0      0 49152      0 LISTEN
      *.microsoft-ds       *.*                0      0 49152      0 LISTEN
rvl4.32801           rvl4.32788           49152      0 49152      0 ESTABLISHED
rvl4.32788           rvl4.32801           49152      0 49196      0 ESTABLISHED
      *.32803              *.*                0      0 49152      0 LISTEN
      *.32804              *.*                0      0 49152      0 LISTEN
      *.nfsd               *.*                0      0 1049200      0 LISTEN
      *.nfsd               *.*                0      0 1048952      0 LISTEN
rvl4.ssh             moonshine.34064      64128      0 49232      0 ESTABLISHED
      *.ssh                *.*                0      0 49152      0 LISTEN
rvl4.ssh             moonshine.34065      730368      0 49232      0 ESTABLISHED
localhost.6010             *.*                0      0 65535      0 LISTEN
rvl4.ssh             moonshine.34066      113920      0 49232      0 ESTABLISHED
      *.utdsd              *.*                0      0 65535      0 LISTEN
      *.vnetd              *.*                0      0 65535      0 LISTEN
rvl4.ssh             moonshine.34067      64128      0 49232      0 ESTABLISHED
localhost.32807      localhost.32769      57260      0 73620      0 ESTABLISHED
rvl4.ssh             moonshine.34068      64128      0 49232      0 ESTABLISHED
localhost.32769      localhost.32807      73620      0 57409      0 ESTABLISHED
      *.bpcd               *.*                0      0 65535      0 LISTEN
localhost.32810      localhost.32769      57260      0 73620      0 ESTABLISHED
localhost.32769      localhost.32810      73620      0 57260      0 ESTABLISHED
localhost.5987             *.*                0      0 65535      0 LISTEN
localhost.898              *.*                0      0 65535      0 LISTEN
localhost.32816            *.*                0      0 65535      0 LISTEN
localhost.5988             *.*                0      0 65535      0 LISTEN
localhost.32817            *.*                0      0 65535      0 LISTEN
      *.www                *.*                0      0 65535      0 LISTEN
      *.*                  *.*                0      0 65535      0 IDLE
      *.iperf              *.*                0      0 65535      0 LISTEN
localhost.bwnfsd           *.*                0      0 65535      0 LISTEN
rvl4.ssh             xoanon.47116         277344      0 49232      0 ESTABLISHED
localhost.6011             *.*                0      0 65535      0 LISTEN
localhost.utauthd-cb localhost.34721      73620      0 73620      0 TIME_WAIT

TCP: IPv6
   Local Address                     Remote Address                 Swind Send-Q Rwind Recv-Q   State      If
--------------------------------- --------------------------------- ----- ------ ----- ------ ----------- -----
      *.*                               *.*                             0      0 49152      0 IDLE
::1.6012                                *.*                             0      0 65535      0 LISTEN
      *.32840                           *.*                             0      0 65535      0 BOUND
      *.utauthd-cb                      *.*                             0      0 65535      0 LISTEN
      *.utauthd                         *.*                             0      0 65535      0 LISTEN
      *.1556                            *.*                             0      0 49152      0 LISTEN
      *.sunrpc                          *.*                             0      0 49152      0 LISTEN
      *.*                               *.*                             0      0 49152      0 IDLE
      *.32776                           *.*                             0      0 49152      0 LISTEN
      *.32778                           *.*                             0      0 49152      0 LISTEN
      *.6002                            *.*                             0      0 65535      0 LISTEN
      *.icd_db                          *.*                             0      0 49152      0 BOUND
      *.32780                           *.*                             0      0 49152      0 LISTEN
      *.32782                           *.*                             0      0 49152      0 LISTEN
      *.lockd                           *.*                             0      0 1049200      0 LISTEN
      *.32784                           *.*                             0      0 49152      0 LISTEN
      *.32786                           *.*                             0      0 1049200      0 LISTEN
      *.32789                           *.*                             0      0 49152      0 LISTEN
      *.fs                              *.*                             0      0 49152      0 LISTEN
      *.32791                           *.*                             0      0 49152      0 LISTEN
      *.32793                           *.*                             0      0 49152      0 LISTEN
      *.32795                           *.*                             0      0 49152      0 LISTEN
      *.32797                           *.*                             0      0 49152      0 LISTEN
      *.finger                          *.*                             0      0 49152      0 LISTEN
      *.shell                           *.*                             0      0 49152      0 LISTEN
      *.32799                           *.*                             0      0 49152      0 LISTEN
      *.32803                           *.*                             0      0 49152      0 LISTEN
      *.nfsd                            *.*                             0      0 1049200      0 LISTEN
      *.ssh                             *.*                             0      0 49152      0 LISTEN
::1.6010                                *.*                             0      0 65535      0 LISTEN
      *.www                             *.*                             0      0 65535      0 LISTEN
::1.6011                                *.*                             0      0 65535      0 LISTEN

SCTP:
        Local Address                   Remote Address          Swind  Send-Q Rwind  Recv-Q StrsI/O  State
------------------------------- ------------------------------- ------ ------ ------ ------ ------- -----------
0.0.0.0                         0.0.0.0                              0      0 102400      0  32/32  CLOSED

Cisco

Here is the output of show tcp brief

TCB       Local Address           Foreign Address        (state)
0015A2F0  cisco2514-e0.kc9.23     gateway.kc9rg.or.40704 ESTAB

Here is the output of show tcp

tty2, virtual tty from host laptop.kc9rg.org
Connection state is ESTAB, I/O status: 1, unread input bytes: 1
Local host: 10.1.1.254, Local port: 23
Foreign host: 10.1.1.230, Foreign port: 40704

Enqueued packets for retransmit: 1, input: 0  mis-ordered: 0 (0 bytes)

Event Timers (current time is 0xD94AC):
Timer          Starts    Wakeups            Next
Retrans           319          0         0xD967F
TimeWait            0          0             0x0
AckHold           301         16             0x0
SendWnd             0          0             0x0
KeepAlive           0          0             0x0
GiveUp              0          0             0x0
PmtuAger            0          0             0x0
DeadWait            0          0             0x0

iss:  877581589  snduna:  877618999  sndnxt:  877619561     sndwnd:  16384
irs: 2394131764  rcvnxt: 2394132196  rcvwnd:       3697  delrcvwnd:    431

SRTT: 300 ms, RTTO: 607 ms, RTV: 3 ms, KRTT: 0 ms
minRTT: 4 ms, maxRTT: 368 ms, ACK hold: 200 ms
Flags: passive open, higher precedence, retransmission timeout

Datagrams (max data segment is 1460 bytes):
Rcvd: 481 (out of order: 0), with data: 302, total data bytes: 432
Sent: 398 (retransmit: 0), with data: 381, total data bytes: 38398

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