diff -Naur batv-milter-0.3.0/batv-filter/batv-filter.c batv-milter-0.3.0-pa/batv-filter/batv-filter.c
--- batv-milter-0.3.0/batv-filter/batv-filter.c	2009-06-18 14:12:31.000000000 +0200
+++ batv-milter-0.3.0-pa/batv-filter/batv-filter.c	2009-06-18 14:17:52.000000000 +0200
@@ -526,6 +526,14 @@
 		return SMFIS_TEMPFAIL;
 	}
 
+	if (addr == NULL)
+	{
+		if (dolog)
+			syslog(LOG_ERR, "mlfi_connect(): addr == NULL");
+
+		return SMFIS_TEMPFAIL;
+	}
+
 	bfc->ctx_hostname = strdup(hostname);
 	memcpy(&bfc->ctx_addr, addr, sizeof bfc->ctx_addr);