clarify usage of shutdown signals

[l2tpns.git] / Docs / manual.html

diff --git a/Docs/manual.html b/Docs/manual.html
index 4db3a83..ff7f0b3 100644 (file)
--- a/Docs/manual.html
+++ b/Docs/manual.html
@@ -56,6 +56,7 @@ H3 {
     <LI><A HREF="#Filtering">Filtering</A></LI>
     <LI><A HREF="#Clustering">Clustering</A></LI>
     <LI><A HREF="#Routing">Routing</A></LI>
+    <LI><A HREF="#AvoidingFragmentation">Avoiding Fragmentation</A></LI>
     <LI><A HREF="#Performance">Performance</A></LI>
 </OL>
 
@@ -695,12 +696,14 @@ killall -HUP l2tpns
 </PRE>
 
 The signals understood are:
-<UL>
-<LI>SIGHUP - Reload the config from disk and re-open log file</LI>
-<LI>SIGTERM / SIGINT - Shut down.</LI>
-<LI>SIGQUIT - Shut down cleanly.  This will send a disconnect message for
-every active session and tunnel before shutting down.</LI>
-</UL>
+<DL>
+<DT>SIGHUP</DT><DD>Reload the config from disk and re-open log file.</DD>
+<DT>SIGTERM, SIGINT</DT><DD>Stop process.  Tunnels and sessions are not
+terminated.  This signal should be used to stop l2tpns on a
+<A HREF="#Clustering">cluster node</A> where there are other machines to
+continue handling traffic.</DD>
+<DT>SIGQUIT</DT><DD>Shut down: closes sessions and tunnels.</DD>
+</DL>
 
 <H2 ID="Throttling">Throttling</H2>
 
@@ -1030,6 +1033,22 @@ ibgp" for IBGP.  If this is not supported by your IOS revision, you
 can use "maximum-paths" (which works for EBGP) and set
 <B>as_number</B> to a private value such as 64512.<P>
 
+<H2 ID="AvoidingFragmentation">Avoiding Fragmentation</H2>
+
+Fragmentation of encapsulated return packets to the LAC may be avoided
+for TCP sessions by adding a firewall rule to clamps the MSS on
+outgoing SYN packets.
+
+The following is appropriate for interfaces with a typical MTU of
+1500:
+
+<pre>
+iptables -A FORWARD -i tun+ -o eth0    \
+    -p tcp --tcp-flags SYN,RST SYN     \
+    -m tcpmss --mss 1413:1600          \
+    -j TCPMSS --set-mss 1412
+</pre>
+
 <H2 ID="Performance">Performance</H2>
 
 Performance is great.<P>