diff --git a/CHANGELOG b/CHANGELOG
index b55396a87..2b2ee9bd1 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 # Nmap Changelog ($Id$); -*-text-*-
 
+o Added a --nsock-engine option to nmap, nping and ncat to enforce use of a
+  given nsock IO engine. [Henri]
+
 o [NSE] Added support to broadcast-listener for extracting address, native vlan
   and management IP address from CDP packets. [Tom]
 	
diff --git a/docs/refguide.xml b/docs/refguide.xml
index bcf38e31a..fcb70f0b3 100644
--- a/docs/refguide.xml
+++ b/docs/refguide.xml
@@ -2860,6 +2860,23 @@ worth the extra time.</para>
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><option>--nsock-engine
+        epoll|select</option>
+        <indexterm><primary><option>--nsock-engine</option></primary></indexterm>
+        <indexterm><primary>Nsock IO engine</primary></indexterm>
+        </term>
+        <listitem>
+
+<para>Enforce use of a given nsock IO multiplexing engine. Only the
+<literal>select(2)</literal>-based fallback engine is guaranteed to be
+available on your system.  Engines are named after the name of the IO
+management facility they leverage.  Engines currenty implemented are
+<literal>epoll</literal> and <literal>select</literal>.</para>
+
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term>
           <option>-T
diff --git a/ncat/ncat_main.c b/ncat/ncat_main.c
index c136c050d..21cd2403d 100644
--- a/ncat/ncat_main.c
+++ b/ncat/ncat_main.c
@@ -262,6 +262,7 @@ int main(int argc, char *argv[])
         {"proxy",           required_argument,  NULL,         0},
         {"proxy-type",      required_argument,  NULL,         0},
         {"proxy-auth",      required_argument,  NULL,         0},
+        {"nsock-engine",    required_argument,  NULL,         0},
 #ifdef HAVE_OPENSSL
         {"ssl",             no_argument,        &o.ssl,       1},
         {"ssl-cert",        required_argument,  NULL,         0},
@@ -412,6 +413,10 @@ int main(int argc, char *argv[])
                         bye("You can't specify more than one --proxy-auth.");
                 o.proxy_auth = Strdup(optarg);
             }
+            else if (strcmp(long_options[option_index].name, "nsock-engine") == 0)
+            {
+                nsock_set_default_engine(optarg);
+            }
             else if (strcmp(long_options[option_index].name, "broker") == 0)
             {
                 o.broker = 1;
diff --git a/nmap.cc b/nmap.cc
index cc9d71ea9..c6b0a5c9c 100644
--- a/nmap.cc
+++ b/nmap.cc
@@ -573,6 +573,8 @@ void parse_options(int argc, char **argv) {
       {"source-port", required_argument, 0, 'g'},
       {"randomize_hosts", no_argument, 0, 0},
       {"randomize-hosts", no_argument, 0, 0},
+      {"nsock_engine", required_argument, 0, 0},
+      {"nsock-engine", required_argument, 0, 0},
       {"osscan_limit", no_argument, 0, 0}, /* skip OSScan if no open ports */
       {"osscan-limit", no_argument, 0, 0}, /* skip OSScan if no open ports */
       {"osscan_guess", no_argument, 0, 0}, /* More guessing flexability */
@@ -793,6 +795,8 @@ void parse_options(int argc, char **argv) {
                  || strcmp(long_options[option_index].name, "rH") == 0) {
         o.randomize_hosts = 1;
         o.ping_group_sz = PING_GROUP_SZ * 4;
+      } else if (optcmp(long_options[option_index].name, "nsock-engine") == 0) {
+        nsock_set_default_engine(optarg);
       } else if (optcmp(long_options[option_index].name, "osscan-limit")  == 0) {
         o.osscan_limit = 1;
       } else if (optcmp(long_options[option_index].name, "osscan-guess")  == 0
@@ -2111,6 +2115,7 @@ void nmap_free_mem() {
   free_services();
   AllProbes::service_scan_free();
   traceroute_hop_cache_clear();
+  nsock_set_default_engine(NULL);
 }
 
 /* Reads in a (normal or machine format) Nmap log file and gathers enough
diff --git a/nping/ArgParser.cc b/nping/ArgParser.cc
index 54a2fe6fa..06518fb7e 100644
--- a/nping/ArgParser.cc
+++ b/nping/ArgParser.cc
@@ -271,6 +271,7 @@ char errstr[256];
   {"send-ip", no_argument, 0, 0},
   {"bpf-filter", required_argument, 0, 0},
   {"filter", required_argument, 0, 0},
+  {"nsock-engine", required_argument, 0, 0},
   {"no-capture", no_argument, 0, 'N'},
   {"hide-sent", no_argument, 0, 'H'},
     
@@ -954,7 +955,9 @@ char errstr[256];
         o.setBPFFilterSpec( optarg );
         if( o.issetDisablePacketCapture() && o.disablePacketCapture()==true )
             outError(QT_2, "Warning: There is no point on specifying a BPF filter if you disable packet capture. BPF filter will be ignored.");
-        
+    } else if (optcmp(long_options[option_index].name, "nsock-engine") == 0){
+        nsock_set_default_engine(optarg);
+
     /* Output Options */
     } else if (optcmp(long_options[option_index].name, "quiet") == 0 ){
             o.setVerbosity(-4);
diff --git a/nsock/include/nsock.h b/nsock/include/nsock.h
index 38c0db55e..8f2a7fa69 100644
--- a/nsock/include/nsock.h
+++ b/nsock/include/nsock.h
@@ -193,6 +193,14 @@ nsock_ssl_ctx nsp_ssl_init(nsock_pool ms_pool);
  * verification is done. Returns the SSL_CTX so you can set your own options. */
 nsock_ssl_ctx nsp_ssl_init_max_speed(nsock_pool ms_pool);
 
+/* Enforce use of a given IO engine.
+ * The engine parameter is a zero-terminated string that will be
+ * strup()'ed by the library. No validity check is performed by this function,
+ * beware nsp_new() will fatal() if an invalid/unavailable engine name was
+ * supplied before.
+ * Pass NULL to reset to default (use most efficient engine available). */
+void nsock_set_default_engine(char *engine);
+
 /* And here is how you create an nsock_pool.  This allocates, initializes, and
  * returns an nsock_pool event aggregator.  In the case of error, NULL will be
  * returned.  If you do not wish to immediately associate any userdata, pass in
diff --git a/nsock/src/nsock_engines.c b/nsock/src/nsock_engines.c
index c0517d759..a13b5e23c 100644
--- a/nsock/src/nsock_engines.c
+++ b/nsock/src/nsock_engines.c
@@ -83,8 +83,10 @@ static struct io_engine *available_engines[] = {
   NULL
 };
 
+static char *engine_hint;
 
-struct io_engine *get_io_engine(const char *engine_hint) {
+
+struct io_engine *get_io_engine(void) {
   struct io_engine *engine = NULL;
   int i;
 
@@ -105,3 +107,13 @@ struct io_engine *get_io_engine(const char *engine_hint) {
   return engine;
 }
 
+void nsock_set_default_engine(char *engine) {
+  if (engine_hint)
+    free(engine_hint);
+
+  if (engine)
+    engine_hint = strdup(engine);
+  else
+    engine_hint = NULL;
+}
+
diff --git a/nsock/src/nsock_pool.c b/nsock/src/nsock_pool.c
index 06e2d0236..55ed0841d 100644
--- a/nsock/src/nsock_pool.c
+++ b/nsock/src/nsock_pool.c
@@ -81,7 +81,7 @@ static int nsocklib_initialized = 0;
 
 
 /* defined in nsock_engines.h */
-struct io_engine *get_io_engine(const char *engine_hint);
+struct io_engine *get_io_engine(void);
 
 /* ---- INTERNAL FUNCTIONS PROTOTYPES ---- */
 static void nsock_library_initialize(void);
@@ -170,7 +170,7 @@ nsock_pool nsp_new(void *userdata) {
 
   nsp->userdata = userdata;
 
-  nsp->engine = get_io_engine(NULL);
+  nsp->engine = get_io_engine();
   nsp->engine->init(nsp);
 
   /* initialize IO events lists */