no warning for . in interface names (vlan)
diff --git a/iptables.c b/iptables.c
index 35adc2b..07de896 100644
--- a/iptables.c
+++ b/iptables.c
@@ -751,7 +751,9 @@
 		memset(mask, 0xFF, vialen + 1);
 		memset(mask + vialen + 1, 0, IFNAMSIZ - vialen - 1);
 		for (i = 0; vianame[i]; i++) {
-			if (!isalnum(vianame[i]) && vianame[i] != '_') {
+			if (!isalnum(vianame[i]) 
+			    && vianame[i] != '_' 
+			    && vianame[i] != '.') {
 				printf("Warning: wierd character in interface"
 				       " `%s' (No aliases, :, ! or *).\n",
 				       vianame);