-# Alternatively (or additionally, if you like) use userv-ipif to get
-# packets to and from the kernel.
-#netlink userv-ipif {
-# name "netlink-userv-ipif";
-# # userv-path "/usr/bin/userv";
-# # service-user "root";
-# # service-name "ipif";
-# networks "whatever";
-# local-address "whatever";
-# secnet-address "whatever";
-# mtu 1400;
-# buffer sysbuffer(2048);
-#};
+# This alternative configuration allows you to create one kernel network
+# interface per tunnel. IT WILL ONLY WORK WITH "tun" - IT WILL NOT
+# WORK WITH "userv-ipif". This is because "tun" can share a single
+# buffer between multiple network interfaces, but userv-ipif can't.
+# To use userv-ipif in this style, process the sites.conf file so that
+# each "netlink" section contains a "buffer sysbuffer(2048);" line.
+#netlink tun;
+#local-address "192.168.x.x"; # Address of local interfaces - all the same
+#mtu 1400;
+#buffer sysbuffer(2048);
+
+# This is small enough that it fits without fragmentation into
+# the foolish wifi on Greater Anglia's now-retired Class 379s.
+# This is good because they mishandle fragmentation.
+mtu-target 1260;
+