diff --git a/smbclientng/__main__.py b/smbclientng/__main__.py
index 1f8e865..5277051 100644
--- a/smbclientng/__main__.py
+++ b/smbclientng/__main__.py
@@ -31,7 +31,7 @@ def parseArgs():
 
     authconn = parser.add_argument_group("Authentication & connection")
     authconn.add_argument("--kdcHost", dest="kdcHost", action="store", metavar="FQDN KDC", help="FQDN of KDC for Kerberos.")
-    authconn.add_argument("-d", "--domain", dest="auth_domain", metavar="DOMAIN", action="store", help="(FQDN) domain to authenticate to")
+    authconn.add_argument("-d", "--domain", dest="auth_domain", metavar="DOMAIN", action="store", default='.', help="(FQDN) domain to authenticate to")
     authconn.add_argument("-u", "--user", dest="auth_username", metavar="USER", action="store", help="user to authenticate with")
 
     secret = parser.add_argument_group()