Document Linux VLAN needs in README section on Linux.

diff --git a/README b/README
index 0f7d01d7b567da75ceee3d8031533e8d5e9fe902..6c96ae626f7f63e66c16e02a82ff14e1e886d150 100644 (file)
--- a/README
+++ b/README
@@ -367,6 +367,18 @@ Linux 2.1 and later kernels do not use SO_BINDTODEVICE or require the
 broadcast address hack, but do support multiple interfaces, using the
 Linux Packet Filter.
 
+                   LINUX: 802.1q VLAN INTERFACES
+
+If you're using 802.1q vlan interfaces on Linux, it is necessary to
+vconfig the subinterface(s) to rewrite the 802.1q information out of
+packets received by the dhcpd daemon via LPF:
+
+       vconfig set_flag eth1.523 1 1
+
+Note that this may affect the performance of your system, since the
+Linux kernel must rewrite packets received via this interface.  For
+more information, consult the vconfig man pages.
+
                                 SCO
 
 SCO has the same problem as Linux (described earlier).  The thing is,