(previously posted as
The way zabbix 1.4.2 implements ip_in_list is buggy. As you strcmp the ip and the range, the comparison will fail in the following example:
First, you strcmp(10.0.0.30,10.0.0.1) and get, as expected, >0. Then, however, you strcmp(10.0.0.30,10.0.0.255) which, as 3 > 2, will also return >0.
I have created a patch to fix this by actually comparing the int values. While I'm sure there's a more c-ish way to do this, it seems to work.