Skip to content
  1. Mar 03, 1998
  3. Feb 28, 1998
  5. Feb 26, 1998
  7. Feb 25, 1998
  9. Feb 24, 1998
  11. Feb 23, 1998
  13. Feb 20, 1998
  15. Feb 18, 1998
  17. Feb 15, 1998
  19. Feb 14, 1998
  21. Feb 12, 1998
  23. Feb 11, 1998
  25. Feb 07, 1998
  27. Feb 05, 1998
  29. Feb 04, 1998
  31. Feb 03, 1998
  33. Feb 01, 1998
  35. Jan 30, 1998
  37. Jan 28, 1998
  39. Jan 26, 1998
    • lookit's avatar
      Server-generated pages can be server-signed now (new directive) · 195d88e2
      lookit authored 
      
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@80023 13f79535-47bb-0310-9956-ffa450edef68
      195d88e2
    • Ken Coar's avatar
      A truly mighty mod normalising HTML tags to uppercase, and · 77d6039c
      Ken Coar authored 
      	'i' and 'b' to 'EM' and 'STRONG' respectively.  Been threatening
	to do this for months.. no-one need try to maintain this when
	writing/modifiying the docs.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@80021 13f79535-47bb-0310-9956-ffa450edef68
      77d6039c
    • brian's avatar
      PR: · eaeb52c6
      brian authored 
      tsk tsk, randy.  Can't find this on covalent.net either.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@80015 13f79535-47bb-0310-9956-ffa450edef68
      eaeb52c6
    • brian's avatar
      PR: · 52374e06
      brian authored 
      David Robinson's CGI specification is no longer available at this URL.  perhaps
we should point at other CGI resources online?


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@80013 13f79535-47bb-0310-9956-ffa450edef68
      52374e06
    • brian's avatar
      PR: · f9b19ae6
      brian authored 
      If SGI is going to break their links, I'm not about to go ferreting around
their site looking for where they moved it to.  Since the other entry is
generic for all OS's (or at least doesn't clearly state HOW it's related),
I've removed the SGI entry.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@80011 13f79535-47bb-0310-9956-ffa450edef68
      f9b19ae6
    • brian's avatar
      PR: · b6ba7d5b
      brian authored 
      If SCO's going to break their links, I'm not going to go searching for where they
moved it to.

Cold and rainy and dark.
ml" -->

<H1 ALIGN="CENTER">Connections in the FIN_WAIT_2 state and Apache</H1>
<OL>
<LI><H2>What is the FIN_WAIT_2 state?</H2>
Starting with the Apache 1.2 betas, people are reporting many more
connections in the FIN_WAIT_2 state (as reported by
<code>netstat</code>) than they saw using older versions.  When the
server closes a TCP connection, it sends a packet with the FIN bit
sent to the client, which then responds with a packet with the ACK bit
set.  The client then sends a packet with the FIN bit set to the
server, which responds with an ACK and the connection is closed.  The
state that the connection is in during the period between when the
server gets the ACK from the client and the server gets the FIN from
the client is known as FIN_WAIT_2.  See the <A
HREF="ftp://ds.internic.net/rfc/rfc793.txt">TCP RFC</A> for the
technical details of the state transitions.<P>

The FIN_WAIT_2 state is somewhat unusual in that there is no timeout
defined in the standard for it.  This means that on many operating
systems, a connection in the FIN_WAIT_2 state will stay around until
the system is rebooted.  If the system does not have a timeout and
too many FIN_WAIT_2 connections build up, it can fill up the space
allocated for storing information about the connections and crash
the kernel.  The connections in FIN_WAIT_2 do not tie up an httpd
process.<P>

<LI><H2>But why does it happen?</H2>

There are numerous reasons for it happening, some of them may not
yet be fully clear.  What is known follows.<P>

<H3>Buggy clients and persistent connections</H3>

Several clients have a bug which pops up when dealing with
<A HREF="../keepalive.html">persistent connections</A> (aka keepalives).
When the connection is idle and the server closes the connection
(based on the <A HREF="../mod/core.html#keepalivetimeout">
KeepAliveTimeout</A>), the client is programmed so that the client does
not send back a FIN and ACK to the server.  This means that the
connection stays in the FIN_WAIT_2 state until one of the following
happens:<P>
<UL>
        <LI>The client opens a new connection to the same or a different
            site, which causes it to fully close the older connection on
            that socket.
        <LI>The user exits the client, which on some (most?) clients
            causes the OS to fully shutdown the connection.
        <LI>The FIN_WAIT_2 times out, on servers that have a timeout
            for this state.
</UL><P>
If you are lucky, this means that the buggy client will fully close the
connection and release the resources on your server.  However, there
are some cases where the socket is never fully closed, such as a dialup
client disconnecting from their provider before closing the client.
In addition, a client might sit idle for days without making another
connection, and thus may hold its end of the socket open for days
even though it has no further use for it.
<STRONG>This is a bug in the browser or in its operating system's
TCP implementation.</STRONG>  <P>

The clients on which this problem has been verified to exist:<P>
<UL>
        <LI>Mozilla/3.01 (X11; I; FreeBSD 2.1.5-RELEASE i386)
        <LI>Mozilla/2.02 (X11; I; FreeBSD 2.1.5-RELEASE i386)
        <LI>Mozilla/3.01Gold (X11; I; SunOS 5.5 sun4m)
        <LI>MSIE 3.01 on the Macintosh
        <LI>MSIE 3.01 on Windows 95
</UL><P>

This does not appear to be a problem on:
<UL>
        <LI>Mozilla/3.01 (Win95; I)
</UL>
<P>

It is expected that many other clients have the same problem. What a
client <STRONG>should do</STRONG> is periodically check its open
socket(s) to see if they have been closed by the server, and close their
side of the connection if the server has closed.  This check need /export/home/cvs/CVSROOT/cvsedit


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@80009 13f79535-47bb-0310-9956-ffa450edef68
      b6ba7d5b