Merge r1031062 from trunk:

PR#50174: don't offer 120ms as a "typical" TCP keepalive frequency.  Initial keepalive timers can be
as high as 2 hours (windows/linux/solars defaults via google).

Drive home the idea that users need
to figure out their OS and Firewall timers and make the former smaller than th elatter.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1031063 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/mod/mod_proxy.html.en b/docs/manual/mod/mod_proxy.html.en
index f8c02ecff4ed53ba68d1fc18f0a2cb45bbde51be..39310916bfc5252ca544bbce254bede6eece9520 100644 (file)
--- a/docs/manual/mod/mod_proxy.html.en
+++ b/docs/manual/mod/mod_proxy.html.en
@@ -999,12 +999,15 @@ through</td></tr>
     </td></tr>
     <tr><td>keepalive</td>
         <td>Off</td>
-        <td>This parameter should be used when you have a firewall between your
+        <td><p>This parameter should be used when you have a firewall between your
     Apache and the backend server, who tend to drop inactive connections.
     This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
-    messages on inactive connections (interval depends on global OS settings,
-    generally 120ms), and thus prevent the firewall to drop the connection.
-    To enable keepalive set this property value to <code>On</code>. 
+    messages on inactive connections  and thus prevent the firewall to drop the connection.
+    To enable keepalive set this property value to <code>On</code>. </p>
+    <p>The frequency of initial and subsequent TCP keepalive probes 
+    depends on global OS settings, and may be as high as 2 hours. To be useful,
+    the frequency configured in the OS must be smaller than the threshold used 
+    by the firewall.</p>
     </td></tr>
     <tr><td>lbset</td>
         <td>0</td>

diff --git a/docs/manual/mod/mod_proxy.xml b/docs/manual/mod/mod_proxy.xml
index 7bee9b1e49862e469c3e29fe7e7d916d3e1afe88..26b4af475b4920a39d804da0af5a411597d2d1b2 100644 (file)
--- a/docs/manual/mod/mod_proxy.xml
+++ b/docs/manual/mod/mod_proxy.xml
@@ -847,12 +847,15 @@ expressions</description>
     </td></tr>
     <tr><td>keepalive</td>
         <td>Off</td>
-        <td>This parameter should be used when you have a firewall between your
+        <td><p>This parameter should be used when you have a firewall between your
     Apache and the backend server, who tend to drop inactive connections.
     This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
-    messages on inactive connections (interval depends on global OS settings,
-    generally 120ms), and thus prevent the firewall to drop the connection.
-    To enable keepalive set this property value to <code>On</code>. 
+    messages on inactive connections  and thus prevent the firewall to drop the connection.
+    To enable keepalive set this property value to <code>On</code>. </p>
+    <p>The frequency of initial and subsequent TCP keepalive probes 
+    depends on global OS settings, and may be as high as 2 hours. To be useful,
+    the frequency configured in the OS must be smaller than the threshold used 
+    by the firewall.</p>
     </td></tr>
     <tr><td>lbset</td>
         <td>0</td>