(adding sr-dev) Hello, I only had a quick look to the code, but at least the sl module stats seems to look fine: int sl_filter_ACK(struct sip_msg *msg, unsigned int flags, void *bar) [...] if(memcmp(tag_str->s, sl_tag.s, sl_tag.len) == 0) { LM_DBG("SL local ACK found -> dropping it!\n"); update_sl_filtered_acks(); void update_sl_filtered_acks(void) { (*sl_stats)[process_no].filtered_acks++; } unsigned long sl_stats_rcv_acks(void) { sl_stats_update(); return _sl_stats_total.filtered_acks; } Are you not seeing the increase in the received_ACKs statistics? Cheers, Henning -- Henning Westerholt - https://skalatan.de/blog/ Kamailio services - https://gilawa.com<https://gilawa.com/> From: Kaufman &lt;bkaufman(a)bcmone.com&gt; Sent: Mittwoch, 28. Juni 2023 01:52 To: Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.kamailio.org&gt; Subject: [SR-Users] SL absorbed ACK is counted as dropped by core.drop_requests Just checking to see if this is the designed behavior. The SL module will attempt to match ACKs for stateless replies and handle them (absorb them?). The question I have is that it looks as though this ACK gets counted as dropped by the core.drop_requests from the KEX module. Tested using this config: #!KAMAILIO loadmodule "pv" loadmodule "sl" loadmodule "xlog" loadmodule "kex" loadmodule "corex" loadmodule "ctl" modparam("sl", "bind_tm", 0) route { xinfo("[$ci] $rm Request. Src:[$si:$sp] RURI:[$ru] To:[$tu] From:[$fu]\n"); sl_send_reply("404", "Not Found"); } event_route[sl:filtered-ack] { xnotice("sl:filtered-ack ACK [$ci] to local reply absorbed\n"); } Then validate by kamcmd stats.fetch core:drop_requests Is this the designed and "correct" behavior? Kaufman