diff --git a/doc/bird.sgml b/doc/bird.sgml
index 29fcd5a9..258b8420 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -724,7 +724,7 @@ defined by using the <cf>defined( <m>attribute</m> )</cf> operator.
 	Address scope of the network (<cf/SCOPE_HOST/ for addresses local to this host, <cf/SCOPE_LINK/ for those specific for a physical link, <cf/SCOPE_SITE/ and <cf/SCOPE_ORGANIZATION/ for private addresses, <cf/SCOPE_UNIVERSE/ for globally visible addresses).
 
 	<tag><m/int/ preference</tag>
-	Preference of the route. (See the chapter about routing tables.)
+	Preference of the route. Valid values are 0-65535. (See the chapter about routing tables.)
 
 	<tag><m/ip/ from</tag>
 	The router which the route has originated from. Read-only.
diff --git a/filter/filter.c b/filter/filter.c
index 3df0f0c6..9617482a 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -702,6 +702,8 @@ interpret(struct f_inst *what)
     ONEARG;
     if (v1.type != T_INT)
       runtime( "Can't set preference to non-integer" );
+    if ((v1.val.i < 0) || (v1.val.i > 0xFFFF))
+      runtime( "Setting preference value out of bounds" );
     *f_rte = rte_cow(*f_rte);
     (*f_rte)->pref = v1.val.i;
     break;
diff --git a/nest/config.Y b/nest/config.Y
index ad45a0d5..a2c44ab7 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -132,7 +132,7 @@ proto_name:
 proto_item:
    /* EMPTY */
  | PREFERENCE expr {
-     if ($2 < 0 || $2 > 255) cf_error("Invalid preference");
+     if ($2 < 0 || $2 > 0xFFFF) cf_error("Invalid preference");
      this_proto->preference = $2;
    }
  | DISABLED bool { this_proto->disabled = $2; }