--- a/dnstracer.c
+++ b/dnstracer.c
@@ -1619,7 +1619,7 @@
     if (argv[0] == NULL) usage();
 
     // check for a trailing dot
-    strcpy(argv0, argv[0]);
+    strncpy(argv0, argv[0], NS_MAXDNAME);
     if (argv0[strlen(argv[0]) - 1] == '.') argv0[strlen(argv[0]) - 1] = 0;
 
     printf("Tracing to %s[%s] via %s, maximum of %d retries\n",