Understanding the States display

September 3rd, 2007 by Chris Buechler

When viewing your firewall states (Diagnostics -> States), you’ll see the “State” column with entries such as ESTABLISHED:ESTABLISHED, FIN_WAIT_2:FIN_WAIT_2, TIME_WAIT:TIME_WAIT, etc. A question came up on the forum – so what do these mean?

These are standard means of referring to the status of a TCP connection. I found the following diagram from this TCP tutorial, which is an excellent visual display of what these things mean.

4 Responses to “Understanding the States display”

  1. nw Says:

    this seems to just have been drawn right from this rfc:
    http://www.vs.inf.ethz.ch/edu/WS0102/VS/TCP-State-Diagram.html

  2. Chris Buechler Says:

    Sure is, good catch. Though it’s a lot prettier than that ASCII. :)

  3. nw Says:

    This one is a little nicer because of the extra boxes showing “active close” and “passive close” (From “Computer Networks” by Andrew S. Tannenbaum.) – it makes it look a little more like playing a board game : ).
    http://www.cs.hofstra.edu/~cscccl/c333/tcp.gif

  4. LVS ipvs FIN_WAIT at Docunext Technology Blog Says:

    [...] Related info: This link seems to suggest problem is caused by MTU This link has several LVS related switch hardware issues (Cisco) http://www.vs.inf.ethz.ch/edu/WS0102/VS/TCP-State-Diagram.html http://blog.pfsense.org/?p=137 [...]

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