diff --git a/helper.c b/helper.c
index c4f92ff..38d06c7 100644
--- a/helper.c
+++ b/helper.c
@@ -85,7 +85,7 @@ int is_ip(char *str) {
 	}
 
 	/* three dots with upto three digits in before, between and after ? */
-	if (dotcount == 3 && i > 0 && i <= 3)
+	if (*str == '\0' && dotcount == 3 && i > 0 && i <= 3)
 		return 1;
 	else
 		return 0;
@@ -108,8 +108,12 @@ unsigned long getaddress(char *host) {
 	struct hostent* pent;
 	long l, *lp;
 
-	if (is_ip(host))
+	if (strlen(host) == 0) {
+		return 0;
+	}
+	if (is_ip(host)) {
 		return inet_addr(host);
+	}
 
 	/* try the system's own resolution mechanism for dns lookup:
 	 required only for domain names.
@@ -650,13 +654,14 @@ void replace_strings(char *mes, char *strings) {
 #endif
 }
 
-/* insert \r in front of all \n if it is not present allready */
+/* insert \r in front of all \n if it is not present allready
+ * and and a trailing \r\n is not present */
 void insert_cr(char *mes){
 	char *lf, *pos, *backup;
 
 	pos = mes;
 	lf = strchr(pos, '\n');
-	while ((lf != NULL) && (*(--lf) != '\r')) {
+	while ((lf != NULL) && (lf >= mes+1) && (*(--lf) != '\r')) {
 		backup=str_alloc(strlen(lf)+2);
 		strcpy(backup, lf+1);
 		*(lf+1) = '\r';
diff --git a/tests/check_helper.c b/tests/check_helper.c
index 05a1ab5..085d80e 100644
--- a/tests/check_helper.c
+++ b/tests/check_helper.c
@@ -64,6 +64,77 @@ START_TEST (test_str_to_int) {
 }
 END_TEST
 
+START_TEST (test_is_ip) {
+	fail_unless(is_ip("") == 0,
+		"is_ip(\"\") returned %d, instead of 0", is_ip(""));
+	fail_unless(is_ip("0") == 0,
+		"is_ip(\"0\") returned %d, instead of 0", is_ip("0"));
+	fail_unless(is_ip("100") == 0,
+		"is_ip(\"100\") returned %d, instead of 0", is_ip("100"));
+	fail_unless(is_ip("1000") == 0,
+		"is_ip(\"1000\") returned %d, instead of 0", is_ip("1000"));
+	fail_unless(is_ip("1.0") == 0,
+		"is_ip(\"1.0\") returned %d, instead of 0", is_ip("1.0"));
+	fail_unless(is_ip("1.2.0") == 0,
+		"is_ip(\"1.2.0\") returned %d, instead of 0", is_ip("1.2.0"));
+	fail_unless(is_ip("1.2.3.4.5") == 0,
+		"is_ip(\"1.2.3.4.5\") returned %d, instead of 0", is_ip("1.2.3.4.5"));
+	fail_unless(is_ip("1000.0.0.0") == 0,
+		"is_ip(\"1000.0.0.0\") returned %d, instead of 0", is_ip("1000.0.0.0"));
+	fail_unless(is_ip("0.1000.0.0") == 0,
+		"is_ip(\"0.1000.0.0\") returned %d, instead of 0", is_ip("0.1000.0.0"));
+	fail_unless(is_ip("0.0.1000.0") == 0,
+		"is_ip(\"0.0.1000.0\") returned %d, instead of 0", is_ip("0.0.1000.0"));
+	fail_unless(is_ip("0.0.0.1000") == 0,
+		"is_ip(\"0.0.0.1000\") returned %d, instead of 0", is_ip("0.0.0.1000"));
+	fail_unless(is_ip("0.0.0.0") == 1,
+		"is_ip(\"0.0.0.0\") returned %d, instead of 1", is_ip("0.0.0.0"));
+	fail_unless(is_ip("1.2.3.4") == 1,
+		"is_ip(\"1.2.3.4\") returned %d, instead of 1", is_ip("1.2.3.4"));
+	fail_unless(is_ip("192.168.1.1") == 1,
+		"is_ip(\"192.168.1.1\") returned %d, instead of 1", is_ip("192.168.1.1"));
+	// this is a "known bug" ;)
+	fail_unless(is_ip("999.999.999.999") == 1,
+		"is_ip(\"999.999.999.999\") returned %d, instead of 1", is_ip("999.999.999.999"));
+}
+END_TEST
+
+START_TEST (test_getaddress) {
+	fail_unless(getaddress("") == 0,
+		"getaddress(\"\") returned %lu, instead of 0", getaddress(""));
+	fail_unless(getaddress("127.0.0.1") == 16777343,
+		"getaddress(\"127.0.0.1\") returned %lu, instead of 16777343", getaddress("127.0.0.1"));
+	// this should work also without DNS
+	fail_unless(getaddress("localhost") == 16777343,
+		"getaddress(\"localhost\") returned %lu, instead of 16777343", getaddress("localhost"));
+}
+END_TEST
+
+START_TEST (test_insert_cr) {
+	char ta[15];
+
+	memset(ta, '\0', 15);
+	insert_cr(ta);
+	fail_unless(memcmp(ta, "\r\n\0\0\0\0\0\0\0\0\0\0\0\0\0", 15) == 0,
+		"insert_cr(\"\") returned '%s', instead of \"\r\n\"", ta);
+	memset(ta, '\0', 15);
+	memcpy(ta, "test", 4);
+	insert_cr(ta);
+	fail_unless(memcmp(ta, "test\r\n\0\0\0\0\0\0\0\0\0", 15) == 0,
+		"insert_cr(\"test\") returned '%s', instead of \"test\r\n\"", ta);
+	memset(ta, '\0', 15);
+	memcpy(ta, "test\n", 5);
+	insert_cr(ta);
+	fail_unless(memcmp(ta, "test\r\n\r\n\0\0\0\0\0\0\0", 15) == 0,
+		"insert_cr(\"test\\n\") returned '%s', instead of \"test\\r\\n\"", ta);
+	memset(ta, '\0', 15);
+	memcpy(ta, "foo\nbar\n", 8);
+	insert_cr(ta);
+	fail_unless(memcmp(ta, "foo\r\nbar\r\n\r\n\0\0\0", 15) == 0,
+		"insert_cr(\"foo\\nbar\\n\") returned '%s', instead of \"foo\\r\\nbar\\r\\n\"", ta);
+}
+END_TEST
+
 Suite *helper_suite(void) {
 	Suite *s = suite_create("Helper");
 
@@ -75,9 +146,24 @@ Suite *helper_suite(void) {
 	TCase *tc_str_to_int = tcase_create("str_to_int");
 	tcase_add_test(tc_str_to_int, test_str_to_int);
 
+	/* is_ip test case */
+	TCase *tc_is_ip = tcase_create("is_ip");
+	tcase_add_test(tc_is_ip, test_is_ip);
+
+	/* getaddress test case */
+	TCase *tc_getaddress = tcase_create("getaddress");
+	tcase_add_test(tc_getaddress, test_getaddress);
+
+	/* insert_cr test case */
+	TCase *tc_insert_cr = tcase_create("insert_cr");
+	tcase_add_test(tc_insert_cr, test_insert_cr);
+
 	/* add test cases to suite */
 	suite_add_tcase(s, tc_is_number);
 	suite_add_tcase(s, tc_str_to_int);
+	suite_add_tcase(s, tc_is_ip);
+	suite_add_tcase(s, tc_getaddress);
+	suite_add_tcase(s, tc_insert_cr);
 
 	return s;
 }