diff --git a/conf/default.conf.php b/conf/default.conf.php
index bc427dcafb..cf9f963d4e 100644
--- a/conf/default.conf.php
+++ b/conf/default.conf.php
@@ -174,7 +174,7 @@ return array(
   'mysql.host' => 'localhost',
 
   // If you want to connect to a different port than the default (which is 3306)
-  'mysql.port' => '3306',
+  'mysql.port' => null,
 
   // Phabricator supports PHP extensions MySQL and MySQLi. It is possible to
   // implement also other access mechanism (e.g. PDO_MySQL). The class must
diff --git a/src/applications/config/check/PhabricatorSetupCheckDatabase.php b/src/applications/config/check/PhabricatorSetupCheckDatabase.php
index b0903eabc2..24a2f26a7b 100644
--- a/src/applications/config/check/PhabricatorSetupCheckDatabase.php
+++ b/src/applications/config/check/PhabricatorSetupCheckDatabase.php
@@ -107,5 +107,36 @@ final class PhabricatorSetupCheckDatabase extends PhabricatorSetupCheck {
             hsprintf('<tt>phabricator/ $</tt> ./bin/storage upgrade'));
       }
     }
+
+
+    $host = PhabricatorEnv::getEnvConfig('mysql.host');
+    $matches = null;
+    if (preg_match('/^([^:]+):(\d+)$/', $host, $matches)) {
+      $host = $matches[1];
+      $port = $matches[2];
+
+      $this->newIssue('storage.mysql.hostport')
+        ->setName(pht('Deprecated mysql.host Format'))
+        ->setSummary(
+          pht(
+            'Move port information from `mysql.host` to `mysql.port` in your '.
+            'config.'))
+        ->setMessage(
+          pht(
+            'Your `mysql.host` configuration contains a port number, but '.
+            'this usage is deprecated. Instead, put the port number in '.
+            '`mysql.port`.'))
+        ->addPhabricatorConfig('mysql.host')
+        ->addPhabricatorConfig('mysql.port')
+        ->addCommand(
+          hsprintf(
+            '<tt>phabricator/ $</tt> ./bin/config set mysql.host %s',
+            $host))
+        ->addCommand(
+          hsprintf(
+            '<tt>phabricator/ $</tt> ./bin/config set mysql.port %s',
+            $port));
+    }
+
   }
 }