update README with highly non-portable capability support on some linux kernels

diff --git a/README b/README
index 001e6b457814163380b105cc3b91f7d07c8923c2..24b1f00ec6916b469f8bce70e572a6ac7e26b991 100644 (file)
--- a/README
+++ b/README
@@ -35,6 +35,19 @@ ports from connecting.
 These servers require you use the "insecure" export option in /etc/exports
 in order to allow libnfs clients to be able to connect.
 
+Some versions of Linux support special capabilities that can be assigned to
+programs to allow non-root users to bind to system ports.
+This is set up by running 
+    sudo setcap 'cap_net_bind_service=+ep' /path/to/executable
+When libnfs is linked against an executable with this special capability
+assigned to it, libnfs may be able to use system ports even when executing
+under the privilege of a non-root user account.
+
+This is highly non-portable so IF this works on your linux system, count
+yourself lucky.
+
+
+
 PLATFORM support
 =================
 As of now this is tested with linux, MacOSX and Apple iOS.