diff --git a/CHANGES b/CHANGES
index c9a8b7b32a..3bce1e270e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+5758.	[bug]		mdig now honors the operating system's preferred
+			ephemeral port range. [GL #2374]
+
 5757.	[test]		Replace sed in nsupdate system test with awk to
 			construct the nsupdate command.  The sed expression
 			was not reliably changing the ttl. [GL #3003]
diff --git a/bin/tools/mdig.c b/bin/tools/mdig.c
index 364b18cbeb..d1f3ac3891 100644
--- a/bin/tools/mdig.c
+++ b/bin/tools/mdig.c
@@ -27,6 +27,7 @@
 #include <isc/netmgr.h>
 #include <isc/nonce.h>
 #include <isc/parseint.h>
+#include <isc/portset.h>
 #include <isc/print.h>
 #include <isc/random.h>
 #include <isc/result.h>
@@ -2054,6 +2055,47 @@ parse_args(bool is_batchfile, int argc, char **argv) {
 	}
 }
 
+/*
+ * Try honoring the operating system's preferred ephemeral port range.
+ */
+static void
+set_source_ports(dns_dispatchmgr_t *manager) {
+	isc_portset_t *v4portset = NULL, *v6portset = NULL;
+	in_port_t udpport_low, udpport_high;
+	isc_result_t result;
+
+	result = isc_portset_create(mctx, &v4portset);
+	if (result != ISC_R_SUCCESS) {
+		fatal("isc_portset_create (v4) failed");
+	}
+
+	result = isc_net_getudpportrange(AF_INET, &udpport_low, &udpport_high);
+	if (result != ISC_R_SUCCESS) {
+		fatal("isc_net_getudpportrange (v4) failed");
+	}
+
+	isc_portset_addrange(v4portset, udpport_low, udpport_high);
+
+	result = isc_portset_create(mctx, &v6portset);
+	if (result != ISC_R_SUCCESS) {
+		fatal("isc_portset_create (v6) failed");
+	}
+	result = isc_net_getudpportrange(AF_INET6, &udpport_low, &udpport_high);
+	if (result != ISC_R_SUCCESS) {
+		fatal("isc_net_getudpportrange (v6) failed");
+	}
+
+	isc_portset_addrange(v6portset, udpport_low, udpport_high);
+
+	result = dns_dispatchmgr_setavailports(manager, v4portset, v6portset);
+	if (result != ISC_R_SUCCESS) {
+		fatal("dns_dispatchmgr_setavailports failed");
+	}
+
+	isc_portset_destroy(mctx, &v4portset);
+	isc_portset_destroy(mctx, &v6portset);
+}
+
 /*% Main processing routine for mdig */
 int
 main(int argc, char *argv[]) {
@@ -2119,6 +2161,8 @@ main(int argc, char *argv[]) {
 	RUNCHECK(isc_task_create(taskmgr, 0, &task));
 	RUNCHECK(dns_dispatchmgr_create(mctx, netmgr, &dispatchmgr));
 
+	set_source_ports(dispatchmgr);
+
 	if (have_ipv4) {
 		isc_sockaddr_any(&bind_any);
 	} else {