diff --git a/src/accept.c b/src/accept.c
index 791c6bf..42a748a 100644
--- a/src/accept.c
+++ b/src/accept.c
@@ -1475,8 +1475,8 @@ void accept_thread(void *asdf)
 				n++;
 			}
 			hlog(LOG_INFO, "Accept thread ready.");
-			historydb_enabled = has_filtered_listeners_now;
-			if (!historydb_enabled)
+			have_filtered_listeners = has_filtered_listeners_now;
+			if (!have_filtered_listeners)
 				hlog(LOG_INFO, "Disabled historydb, listeners do not have filtering enabled.");
 			
 			/* stop the dupechecking and uplink threads while adjusting
diff --git a/src/dupecheck.c b/src/dupecheck.c
index eb42b1d..276d4b6 100644
--- a/src/dupecheck.c
+++ b/src/dupecheck.c
@@ -40,8 +40,6 @@ int dupecheck_running;
 pthread_t dupecheck_th;
 long dupecheck_cellgauge;
 
-int historydb_enabled;  /* historydb inserts enabled only if filtering available */
-
 int pbuf_global_count;
 int pbuf_global_dupe_count;
 
@@ -656,7 +654,7 @@ static int dupecheck_drain_worker(struct worker_t *w,
 			 * is enabled (disabled if no filtered listeners
 			 * configured, for memory savings)
 			 */
-			if (historydb_enabled) {
+			if (have_filtered_listeners) {
 				historydb_insert(pb);
 				filter_postprocess_dupefilter(pb);
 			}
diff --git a/src/dupecheck.h b/src/dupecheck.h
index 2c1f331..40acfdd 100644
--- a/src/dupecheck.h
+++ b/src/dupecheck.h
@@ -41,7 +41,6 @@ extern long long dupecheck_dupecount; /* statistics counter */
 extern long long dupecheck_dupetypes[DTYPE_MAX+1];
 extern long      dupecheck_cellgauge; /* statistics gauge   */
 
-extern int historydb_enabled;
 extern int dupecheck_eventfd;
 
 extern int  outgoing_lag_report(struct worker_t *self, int*lag, int*dupelag);
diff --git a/src/filter.c b/src/filter.c
index 3b58bd6..089a654 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -239,6 +239,7 @@ cellarena_t *filter_entrycall_cells;
 cellarena_t *filter_wx_cells;
 #endif
 
+int have_filtered_listeners;  /* do we have any filtered listeners, do we need to support them */
 
 #define HIST_LOOKUP_INTERVAL 10 /* Cache historydb position lookups this much seconds on
 				  each filter entry referring to some
@@ -801,9 +802,12 @@ static void filter_keyhashes(struct pbuf_t *pb)
 
 void filter_preprocess_dupefilter(struct pbuf_t *pbuf)
 {
+	// TODO: could probably skip filter_check_tcpip, and possibly filter_keyhashes too if no filtered listeners
 	filter_check_tcpip(pbuf);
-	filter_entrycall_insert(pbuf);
-	filter_wx_insert(pbuf);
+	if (have_filtered_listeners) {
+		filter_entrycall_insert(pbuf);
+		filter_wx_insert(pbuf);
+	}
 	filter_keyhashes(pbuf);
 }
 
diff --git a/src/filter.h b/src/filter.h
index a0098f1..bcc8fb2 100644
--- a/src/filter.h
+++ b/src/filter.h
@@ -35,6 +35,8 @@ extern void filter_wx_dump(FILE *fp);
 
 extern int  filter_cellgauge;
 
+extern int have_filtered_listeners;
+
 extern float filter_lat2rad(float lat);
 extern float filter_lon2rad(float lon);