Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide

NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Read offline with no ads or diagram watermarks!
The TCP/IP Guide

Custom Search

Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  TCP/IP Key Applications and Application Protocols
           9  TCP/IP Administration and Troubleshooting Utilities and Protocols

Previous Topic/Section
TCP/IP DNS Registry Database Lookup Utility (whois/nicname)
Previous Page
Pages in Current Topic/Section
Next Page
TCP/IP Configuration Utilities (ipconfig, winipcfg and ifconfig)
Next Topic/Section

TCP/IP Network Status Utility (netstat)
(Page 4 of 6)

Sample UNIX netstat Output

The netstat command can produce a startling amount of output, especially if you do not restrict it with some of the options in Table 297. This is particularly true for netstat by itself and with the “-s” option. In Table 298 I have shown sample output from running “plain” netstat, but I have truncated the list of connections so it would not be too long (I also reformatted the table so it would display better). Notice the last column, which shows the current state of the TCP connection (see, that TCP finite state machine stuff was useful after all! J) Table 299 shows an example of the output of “netstat -s”; here I have shortened the size of the output by using “-p ip” to tell the program to only show me the statistics for the Internet Protocol.

Table 298: Sample Connections List From UNIX netstat Utility

Active Internet connections
Prot Rcv Snd Local Address Foreign Address (state)
tcp4 0 0 c-24-118-141-124.3384 ESTABLISHED
tcp4 0 827 webcacheB03a.cac.46075 ESTABLISHED
tcp4 0 0 qs36.smtp MV1- ESTABLISHED
tcp4 0 0 1Cust234.tnt1.le.1338 ESTABLISHED
tcp4 0 0 1Cust234.tnt1.le.1337 FIN_WAIT_1
tcp4 0 84 dial81-131-97-70.2902 FIN_WAIT_1
tcp4 0 0 FIN_WAIT_2
tcp4 0 0 FIN_WAIT_2
tcp4 0 0 1Cust234.tnt1.le.1326 TIME_WAIT

Table 299: Sample IP Statistics From UNIX netstat Utility

%netstat -s -p ip
57156204 total packets received
0 bad header checksums
4 with size smaller than minimum
0 with data size < data length
0 with ip length > max ip packet size
0 with header length < data size
0 with data length < header length
0 with bad options
0 with incorrect version number
138 fragments received
6 fragments dropped (dup or out of space)
128 fragments dropped after timeout
2 packets reassembled ok
57085912 packets for this host
24736 packets for unknown/unsupported protocol
0 packets forwarded (0 packets fast forwarded)
44957 packets not forwardable
4 packets received for unknown multicast group
0 redirects sent
66183465 packets sent from this host
177 packets sent with fabricated ip header
0 output packets dropped due to no bufs, etc.
0 output packets discarded due to no route
0 output datagrams fragmented
0 fragments created
0 datagrams that can't be fragmented
0 tunneling packets that can't find gif
22 datagrams with bad address in header

Previous Topic/Section
TCP/IP DNS Registry Database Lookup Utility (whois/nicname)
Previous Page
Pages in Current Topic/Section
Next Page
TCP/IP Configuration Utilities (ipconfig, winipcfg and ifconfig)
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $

Home - Table Of Contents - Contact Us

The TCP/IP Guide (
Version 3.0 - Version Date: September 20, 2005

Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.