req_str = string_sprintf("%sHostname: %s\r\n", req_str, fcrdns);
if (sender_host_address != NULL)
req_str = string_sprintf("%sIP: %s\r\n", req_str, sender_host_address);
req_str = string_sprintf("%sHostname: %s\r\n", req_str, fcrdns);
if (sender_host_address != NULL)
req_str = string_sprintf("%sIP: %s\r\n", req_str, sender_host_address);