PR#50174: don't offer 120ms as a "typical" TCP keepalive frequency. Initial keepaliv...

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/trunk@1031062 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/mod/mod_proxy.html.en b/docs/manual/mod/mod_proxy.html.en
index 22df183d12a4c046917c1cdafc69939b723936f5..81c34adc11095a2fb2f3a606f12232429c78758a 100644 (file)
--- a/docs/manual/mod/mod_proxy.html.en
+++ b/docs/manual/mod/mod_proxy.html.en
@@ -1013,12 +1013,15 @@ 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 httpd 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 c610c5be2b1a2278bc6dbe478d851dfc0c5a1813..fc5dfeb7ba18955553c16a18f72e0dacdc719537 100644 (file)
--- a/docs/manual/mod/mod_proxy.xml
+++ b/docs/manual/mod/mod_proxy.xml
@@ -884,12 +884,15 @@ 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 httpd 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>