Hello, On 11/25/13 1:51 PM, Hugh Waite wrote: It is related to that change, fixing an old issue. The 'null' variable was designed to undefine variables or test if a variable is undefined. An undefined variable is the one that doesn't exits. Like $avp(x) might not be in set at all. Some variables always exists, because they are always declared and initialized to 0 if not other default source of value, such variable is $var(x). So practically a $var(x) cannot be 'null' at any time. Probably with the ser-kamailio integration, the comparison with 'null' (which became to be refered as $null) got the inconsistency bug of actually comparing with 0 instead of returning whether the variable exists or not. So, for the case: $avp(x) = 0; the condition if($avp(x)==$null) was true, while it should have been false because $avp(x) is defined, not offering the true result when there was not $avp(x). In other words, $null should be compared with variables that could be in the situation of an non-exiting value. For your example, $var(ip_trusted) should be compared with 0, or you can compare the $sht(trusted=>$var(srcip)) with $null. Cheers, Daniel -- Daniel-Constantin Mierla - http://www.asipto.com http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda