diff --git a/etc/inc/services.inc b/etc/inc/services.inc
index 0622fe3b6e5..3969efafc1a 100644
--- a/etc/inc/services.inc
+++ b/etc/inc/services.inc
@@ -341,6 +341,7 @@ EOD;
 
 				if ($sm['hostname']) {
 					$dhhostname = str_replace(" ", "_", $sm['hostname']);
+					$dhhostname = str_replace(".", "_", $dhhostname);
 					$dhcpdconf .= "	option host-name {$dhhostname};\n";
 				}
 
diff --git a/usr/local/www/services_dhcp_edit.php b/usr/local/www/services_dhcp_edit.php
index 1124e8fe3fc..e6870821ccd 100755
--- a/usr/local/www/services_dhcp_edit.php
+++ b/usr/local/www/services_dhcp_edit.php
@@ -109,8 +109,14 @@ function staticmaps_sort($ifgui) {
 	/* normalize MAC addresses - lowercase and convert Windows-ized hyphenated MACs to colon delimited */
 	$_POST['mac'] = strtolower(str_replace("-", ":", $_POST['mac']));
 	
-	if (($_POST['hostname'] && !is_hostname($_POST['hostname']))) {
-		$input_errors[] = "A valid host name must be specified.";
+	if ($_POST['hostname']) {
+		if (!is_hostname($_POST['hostname'])) {
+			$input_errors[] = "A valid host name must be specified.";
+		} else {
+			if (strpos($_POST['hostname'],'.')) {
+				$input_errors[] = "A valid hostname is specified, but the domain name part should be omitted";
+			}
+		}
 	}
 	if (($_POST['ipaddr'] && !is_ipaddr($_POST['ipaddr']))) {
 		$input_errors[] = "A valid IP address must be specified.";