diff --git a/DDNS.pm b/DDNS.pm
index 70e042e..280d62d 100644
--- a/DDNS.pm
+++ b/DDNS.pm
@@ -29,7 +29,7 @@ sub _validateOrDie {
     die "No domain provided"
 	unless $dom;
     die "Invalid domain name (must end in a dot)"
-	unless ($dom =~ /^[a-zA-Z0-9\.]+\.$/);
+	unless ($dom =~ /^[a-zA-Z0-9\.\-\_]+\.$/);
 }
 
 sub _lookupOrDie {
diff --git a/bin/add-vhost b/bin/add-vhost
index e0016dd..51c9b4d 100755
--- a/bin/add-vhost
+++ b/bin/add-vhost
@@ -9,7 +9,7 @@ my $host = shift || die "No vhost provided";
 my $master = shift || die "No master DNS IP provided";
 
 die "Hostname must end in a dot"
-    unless ($host =~ /^[a-zA-Z0-9\.]+\.$/);
+    unless ($host =~ /^[a-zA-Z0-9\.\-\_]+\.$/);
 
 my $regex = $RE{net}{IPv4} . '|' . $RE{net}{IPv6};
 die "Master must be an IPv4 or IPv6 address"
diff --git a/bin/del-vhost b/bin/del-vhost
index ee804ef..185a310 100755
--- a/bin/del-vhost
+++ b/bin/del-vhost
@@ -8,7 +8,7 @@ use Regexp::Common qw/net/;
 my $host = shift || die "No vhost provided";
 
 die "Hostname must end in a dot"
-    unless ($host =~ /^[a-zA-Z0-9\.]+\.$/);
+    unless ($host =~ /^[a-zA-Z0-9\-\_\.]+\.$/);
 
 my $ddns = Martnet::DDNS->new();
 $ddns->delvhost($host);