Try to add it in onreply_route using htable but in-memory not in database. Steps : You have to initialize an htable by : modparam("htable", "htable", "counter_404=>size=32;initval=0;autoexpire=600;") And you can increase counter like that (i did not test but i think should give you a clue how to proceed further, the initval is set to 0) I used key as request uri + call-id to have an unique key and the value expired after 600sec. In onreply_route for $rs=="404" ( if response status is 404 add to htable the request uri with conjunction of call-id for allowing the values to expire ) $sht(counter_404=>$T_req($ru)::$ci) = $shtinc(counter_404=>$T_req($ru)::$ci); After that somewhere in beginning of request_route once you receive an INVITE you could check the $ru if its in htable counter_404 and if count is lets say higher than 10 (10 replies 404 in last 10 minutes) you can immediately reply 404. if( $shtcn(counter_404=>$ru::.*) > 10 ) { send_reply(404); exit; } Hope it helps - you need to play a bit with it on test environment. Greetings from Poland Tom pt., 10 sty 2020 o 08:10 Krzysztof Drewicz <kdrewicz(a)cludo.pl> napisał(a):