diff -ur mailfilter-0.8.2_orig/src/header.cc mailfilter-0.8.2/src/header.cc
--- mailfilter-0.8.2_orig/src/header.cc	2009-06-07 03:49:57.000000000 +0200
+++ mailfilter-0.8.2/src/header.cc	2009-08-15 13:05:05.968397778 +0200
@@ -63,7 +63,6 @@
    * domain-literal = "[" *(dtext / quoted-pair) "]"
    */
 
-  char* dom;
   unsigned int l, i;
 
   if (!msgid || !*msgid)
@@ -74,12 +73,12 @@
     return -1;
   if (msgid[0] != '<' || msgid[l-1] != '>')
     return -1;
-  if (!(dom = strrchr (msgid, '@')))
+  if (!(strrchr (msgid, '@')))
     return -1;
 
   /* TODO: complete parser */
   for (i = 0; i < l; i++)
-    if (msgid[i] > 127)
+    if ((unsigned char)msgid[i] > 127)
       return -1;
 
   return 0;