diff --git a/server/core/config.c b/server/core/config.c
index da646f8fd..6937244c3 100644
--- a/server/core/config.c
+++ b/server/core/config.c
@@ -75,6 +75,7 @@
 #include <dbusers.h>
 #include <gw.h>
 #include <maxscale/alloc.h>
+#include <maxscale/limits.h>
 #define PCRE2_CODE_UNIT_WIDTH 8
 #include <pcre2.h>
 
@@ -895,8 +896,8 @@ handle_global_item(const char *name, const char *value)
                 int processor_count = get_processor_count();
                 if (thrcount > processor_count)
                 {
-                    MXS_WARNING("Number of threads set to %d which is greater than"
-                                " the number of processors available: %d",
+                    MXS_WARNING("Number of threads set to %d, which is greater than "
+                                "the number of processors available: %d",
                                 thrcount, processor_count);
                 }
             }
@@ -906,6 +907,14 @@ handle_global_item(const char *name, const char *value)
                 return 0;
             }
         }
+
+        if (gateway.n_threads > MXS_MAX_THREADS)
+        {
+            MXS_WARNING("Number of threads set to %d, which is greater than the "
+                        "hard maximum of %d. Number of threads adjusted down "
+                        "accordingly.", gateway.n_threads, MXS_MAX_THREADS);
+            gateway.n_threads = MXS_MAX_THREADS;
+        }
     }
     else if (strcmp(name, "non_blocking_polls") == 0)
     {
diff --git a/server/include/gwbitmask.h b/server/include/gwbitmask.h
index 7b69c4199..782798907 100644
--- a/server/include/gwbitmask.h
+++ b/server/include/gwbitmask.h
@@ -12,7 +12,9 @@
  * of this software will be governed by version 2 or later of the General
  * Public License.
  */
+
 #include <spinlock.h>
+#include <maxscale/limits.h>
 
 /**
  * @file gwbitmask.h An implementation of an arbitrarily long bitmask
@@ -28,7 +30,7 @@
  */
 
 /* This number MUST an be exact multiple of 8 */
-#define MXS_BITMASK_LENGTH      256      /**< Number of bits in the bitmask */
+#define MXS_BITMASK_LENGTH     (MXS_MAX_THREADS + 1)    /**< Number of bits in the bitmask */
 
 #define MXS_BITMASK_SIZE       (MXS_BITMASK_LENGTH / 8) /**< Number of bytes in the bitmask */
 
diff --git a/server/include/maxscale/limits.h b/server/include/maxscale/limits.h
new file mode 100644
index 000000000..083a255dc
--- /dev/null
+++ b/server/include/maxscale/limits.h
@@ -0,0 +1,24 @@
+#ifndef _MAXSCALE_LIMITS_H
+#define _MAXSCALE_LIMITS_H
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+// This file defines hard limits of MaxScale.
+
+// Thread information is stored in a bitmask whose size must be a
+// multiple of 8. The bitmask is indexed using the thread id that start
+// from 1. Hence, the hard maximum number of threads must be a
+// multiple of 8 minus 1.
+#define MXS_MAX_THREADS 255
+
+#endif