Index: sbin/ipfw/ipfw2.c
===================================================================
--- sbin/ipfw/ipfw2.c
+++ sbin/ipfw/ipfw2.c
@@ -4561,6 +4561,19 @@
 			break;
 
 		case TOK_FRAG:
+			/*
+			 * Compatibility: argument after "frag"
+			 * which is not a frag token equals to "frag offset"
+			 */
+
+			if (((*av != NULL) && (strchr(*av, ',') == NULL)) &&
+				(((strchr(*av, '!') == NULL) && (match_token(f_ipoff, *av) == -1)) ||
+				(**av == '!' && (match_token(f_ipoff, *av + 1) == -1)))) {
+					fill_flags_cmd(cmd, O_FRAG, f_ipoff, NULL);
+					cmd->arg1 = 0x1;
+					break;
+			} 
+
 			fill_flags_cmd(cmd, O_FRAG, f_ipoff, *av);
 			/*
 			 * Compatibility: no argument after "frag"