diff --git a/ChangeLog b/ChangeLog
index e24494a616..c4ddcbdc73 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -49,6 +49,8 @@ Bugfix
    * Some example server programs were not sending the close_notify alert.
    * Potential memory leak in mpi_exp_mod() when error occurs during
      calculation of RR.
+   * Improve interoperability by not writing extension length in ClientHello
+     when no extensions are present (found by Matthew Page)
 
 = Version 1.2.10 released 2013-10-07
 Changes
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 2a15da1e9e..15fc554b94 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -212,8 +212,11 @@ static int ssl_write_client_hello( ssl_context *ssl )
     SSL_DEBUG_MSG( 3, ( "client hello, total extension length: %d",
                    ext_len ) );
 
-    *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( ext_len      ) & 0xFF );
+    if( ext_len > 0 )
+    {
+        *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
+        *p++ = (unsigned char)( ( ext_len      ) & 0xFF );
+    }
 
     if ( ssl->hostname != NULL )
     {