diff --git a/net/respondd/src/respondd.c b/net/respondd/src/respondd.c
index 3be8731..47cf6e2 100644
--- a/net/respondd/src/respondd.c
+++ b/net/respondd/src/respondd.c
@@ -621,14 +621,17 @@ int main(int argc, char **argv) {
 				exit(EXIT_FAILURE);
 			}
 
-			// insert the interface delay info at the beginning of the list
-			struct interface_delay_info **head = &if_delay_info_list;
-			struct interface_delay_info *old_head = if_delay_info_list;
+			if (last_ifindex) {
+				// insert the interface delay info at the beginning of the list
+				struct interface_delay_info **head = &if_delay_info_list;
+				struct interface_delay_info *old_head = if_delay_info_list;
+
+				*head = malloc(sizeof(*if_delay_info_list));
+				(*head)->ifindex = last_ifindex;
+				(*head)->max_multicast_delay = max_multicast_delay;
+				(*head)->next = old_head;
+			}
 
-			*head = malloc(sizeof(*if_delay_info_list));
-			(*head)->ifindex = last_ifindex;
-			(*head)->max_multicast_delay = max_multicast_delay;
-			(*head)->next = old_head;
 
 			break;