The module can be used to determine if an address (IP address and port) matches any of the IP subnets stored in cached Kamailio database table. Port 0 in cached database table matches any port. IP address and port to be matched can be either taken from the request (allow_source_address) or given as pvar arguments (allow_address).

Addresses stored in cached database table can be grouped together into one or more groups specified by a group identifier (positive integer value, i.e., equal or greater than 1). Group identifier is given as argument to allow_address and allow_source_address functions.

As a side effect of matching the address, non-NULL tag (see tag_col module parameter) is added as value to peer_tag AVP if peer_tag_avp module parameter has been defined.