diff --git a/CHANGES b/CHANGES
index 2838b49b5b..9b37ab14fe 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+5651.	[func]		Refactor zone dumping to be processed asynchronously
+			via the uv_work_t thread pool API. [GL #2732]
+
 5650.	[bug]		Prevent a crash that could occur if serve-stale
 			was enabled and a prefetch was triggered during a
 			query restart. [GL #2733]
diff --git a/bin/named/server.c b/bin/named/server.c
index 07f853fa95..ba0757348e 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -11487,7 +11487,7 @@ resume:
 				";\n; Cache dump of view '%s' (cache %s)\n;\n",
 				dctx->view->view->name,
 				dns_cache_getname(dctx->view->view->cache));
-			result = dns_master_dumptostreaminc(
+			result = dns_master_dumptostreamasync(
 				dctx->mctx, dctx->cache, NULL, style, dctx->fp,
 				dctx->task, dumpdone, dctx, &dctx->mdctx);
 			if (result == DNS_R_CONTINUE) {
@@ -11547,7 +11547,7 @@ resume:
 				goto nextzone;
 			}
 			dns_db_currentversion(dctx->db, &dctx->version);
-			result = dns_master_dumptostreaminc(
+			result = dns_master_dumptostreamasync(
 				dctx->mctx, dctx->db, dctx->version, style,
 				dctx->fp, dctx->task, dumpdone, dctx,
 				&dctx->mdctx);
diff --git a/config.h.win32 b/config.h.win32
index bd583dbe90..16aab18194 100644
--- a/config.h.win32
+++ b/config.h.win32
@@ -378,15 +378,6 @@ typedef __int64 off_t;
 /* Define to 1 if you have the `SSL_CTX_up_ref' function. */
 #define SSL_CTX_UP_REF 1
 
-/* Define to 1 if you have the `uv_handle_get_data' function. */
-@HAVE_UV_HANDLE_GET_DATA@
-
-/* Define to 1 if you have the `uv_handle_set_data' function. */
-@HAVE_UV_HANDLE_SET_DATA@
-
-/* Define to 1 if you have the `uv_import' function. */
-@HAVE_UV_IMPORT@
-
 /* GSSAPI Related defines */
 @HAVE_GSSAPI@
 @HAVE_GSSAPI_H@
diff --git a/configure.ac b/configure.ac
index 9b99141419..9b947ff4d8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -600,7 +600,10 @@ LIBS="$LIBS $LIBUV_LIBS"
 
 # Those functions are only provided in newer versions of libuv, we'll be emulating them
 # for now
-AC_CHECK_FUNCS([uv_handle_get_data uv_handle_set_data uv_import uv_udp_connect uv_translate_sys_error uv_sleep])
+AC_CHECK_FUNCS([uv_handle_get_data uv_handle_set_data])
+AC_CHECK_FUNCS([uv_req_get_data uv_req_set_data])
+AC_CHECK_FUNCS([uv_udp_connect uv_translate_sys_error uv_sleep])
+AC_CHECK_FUNCS([uv_os_getenv uv_os_setenv])
 AX_RESTORE_FLAGS([libuv])
 
 # libnghttp2
diff --git a/doc/notes/notes-current.rst b/doc/notes/notes-current.rst
index 04f1e8db86..4694b063b5 100644
--- a/doc/notes/notes-current.rst
+++ b/doc/notes/notes-current.rst
@@ -33,6 +33,9 @@ New Features
   became clogged up with queries that are too old and have already timeouted
   on the receiving side. :gl:`#2313`
 
+- Run zone dumping tasks on separate asynchronous thread pools.  This change
+  makes zone dumping no longer block networking I/O. :gl:`#2732`
+
 Removed Features
 ~~~~~~~~~~~~~~~~
 
diff --git a/lib/dns/include/dns/masterdump.h b/lib/dns/include/dns/masterdump.h
index fcfc2e2e74..dbb8ec8026 100644
--- a/lib/dns/include/dns/masterdump.h
+++ b/lib/dns/include/dns/masterdump.h
@@ -243,11 +243,11 @@ dns_dumpctx_db(dns_dumpctx_t *dctx);
 
 /*@{*/
 isc_result_t
-dns_master_dumptostreaminc(isc_mem_t *mctx, dns_db_t *db,
-			   dns_dbversion_t *	     version,
-			   const dns_master_style_t *style, FILE *f,
-			   isc_task_t *task, dns_dumpdonefunc_t done,
-			   void *done_arg, dns_dumpctx_t **dctxp);
+dns_master_dumptostreamasync(isc_mem_t *mctx, dns_db_t *db,
+			     dns_dbversion_t *	       version,
+			     const dns_master_style_t *style, FILE *f,
+			     isc_task_t *task, dns_dumpdonefunc_t done,
+			     void *done_arg, dns_dumpctx_t **dctxp);
 
 isc_result_t
 dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
@@ -259,11 +259,6 @@ dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
  * 'format'.  If the format is dns_masterformat_text (the RFC1035 format),
  * 'style' specifies the file style (e.g., &dns_master_style_default).
  *
- * dns_master_dumptostream() is an old form of dns_master_dumptostream3(),
- * which always specifies the dns_masterformat_text format.
- * dns_master_dumptostream2() is an old form which always specifies
- * a NULL header.
- *
  * If 'format' is dns_masterformat_raw, then 'header' can contain
  * information to be written to the file header.
  *
@@ -276,7 +271,6 @@ dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
  *
  * Returns:
  *\li	ISC_R_SUCCESS
- *\li	ISC_R_CONTINUE	dns_master_dumptostreaminc() only.
  *\li	ISC_R_NOMEMORY
  *\li	Any database or rrset iterator error.
  *\li	Any dns_rdata_totext() error code.
@@ -286,11 +280,11 @@ dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
 /*@{*/
 
 isc_result_t
-dns_master_dumpinc(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
-		   const dns_master_style_t *style, const char *filename,
-		   isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
-		   dns_dumpctx_t **dctxp, dns_masterformat_t format,
-		   dns_masterrawheader_t *header);
+dns_master_dumpasync(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+		     const dns_master_style_t *style, const char *filename,
+		     isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
+		     dns_dumpctx_t **dctxp, dns_masterformat_t format,
+		     dns_masterrawheader_t *header);
 
 isc_result_t
 dns_master_dump(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
@@ -302,11 +296,6 @@ dns_master_dump(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
  * 'format'.  If the format is dns_masterformat_text (the RFC1035 format),
  * 'style' specifies the file style (e.g., &dns_master_style_default).
  *
- * dns_master_dumpinc() and dns_master_dump() are old forms of _dumpinc3()
- * and _dump3(), respectively, which always specify the dns_masterformat_text
- * format.  dns_master_dumpinc2() and dns_master_dump2() are old forms which
- * always specify a NULL header.
- *
  * If 'format' is dns_masterformat_raw, then 'header' can contain
  * information to be written to the file header.
  *
@@ -314,7 +303,6 @@ dns_master_dump(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
  *
  * Returns:
  *\li	ISC_R_SUCCESS
- *\li	ISC_R_CONTINUE	dns_master_dumpinc() only.
  *\li	ISC_R_NOMEMORY
  *\li	Any database or rrset iterator error.
  *\li	Any dns_rdata_totext() error code.
diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
index c66eb7cceb..c5f00bd1c3 100644
--- a/lib/dns/masterdump.c
+++ b/lib/dns/masterdump.c
@@ -265,8 +265,8 @@ struct dns_dumpctx {
 	isc_task_t *task;
 	dns_dumpdonefunc_t done;
 	void *done_arg;
-	unsigned int nodes;
-	/* dns_master_dumpinc() */
+	/* dns_master_dumpasync() */
+	isc_result_t result;
 	char *file;
 	char *tmpfile;
 	dns_masterformat_t format;
@@ -1343,7 +1343,7 @@ dump_rdatasets_map(isc_mem_t *mctx, const dns_name_t *name,
 static const int initial_buffer_length = 1200;
 
 static isc_result_t
-dumptostreaminc(dns_dumpctx_t *dctx);
+dumptostream(dns_dumpctx_t *dctx);
 
 static void
 dumpctx_destroy(dns_dumpctx_t *dctx) {
@@ -1486,27 +1486,23 @@ closeandrename(FILE *f, isc_result_t result, const char *temp,
 	return (result);
 }
 
+/*
+ * This will run in a libuv threadpool thread.
+ */
 static void
-dump_quantum(isc_task_t *task, isc_event_t *event) {
-	isc_result_t result;
-	isc_result_t tresult;
-	dns_dumpctx_t *dctx;
-
-	REQUIRE(event != NULL);
-	dctx = event->ev_arg;
+master_dump_cb(void *data) {
+	isc_result_t result = ISC_R_UNSET;
+	dns_dumpctx_t *dctx = data;
 	REQUIRE(DNS_DCTX_VALID(dctx));
+
 	if (atomic_load_acquire(&dctx->canceled)) {
 		result = ISC_R_CANCELED;
 	} else {
-		result = dumptostreaminc(dctx);
-	}
-	if (result == DNS_R_CONTINUE) {
-		event->ev_arg = dctx;
-		isc_task_send(task, &event);
-		return;
+		result = dumptostream(dctx);
 	}
 
 	if (dctx->file != NULL) {
+		isc_result_t tresult = ISC_R_UNSET;
 		tresult = closeandrename(dctx->f, result, dctx->tmpfile,
 					 dctx->file);
 		if (tresult != ISC_R_SUCCESS && result == ISC_R_SUCCESS) {
@@ -1515,17 +1511,51 @@ dump_quantum(isc_task_t *task, isc_event_t *event) {
 	} else {
 		result = flushandsync(dctx->f, result, NULL);
 	}
+
+	dctx->result = result;
+}
+
+/*
+ * This will run in a network/task manager thread when the dump is complete.
+ */
+static void
+master_dump_done_cb(void *data, isc_result_t result) {
+	dns_dumpctx_t *dctx = data;
+
+	if (result == ISC_R_SUCCESS && dctx->result != ISC_R_SUCCESS) {
+		result = dctx->result;
+	}
+
 	(dctx->done)(dctx->done_arg, result);
-	isc_event_free(&event);
 	dns_dumpctx_detach(&dctx);
 }
 
+/*
+ * This must be run from a network/task manager thread.
+ */
+static void
+setup_dump(isc_task_t *task, isc_event_t *event) {
+	dns_dumpctx_t *dctx = NULL;
+
+	REQUIRE(isc_nm_tid() >= 0);
+	REQUIRE(event != NULL);
+
+	dctx = event->ev_arg;
+
+	REQUIRE(DNS_DCTX_VALID(dctx));
+
+	isc_nm_work_offload(isc_task_getnetmgr(task), master_dump_cb,
+			    master_dump_done_cb, dctx);
+
+	isc_event_free(&event);
+}
+
 static isc_result_t
 task_send(dns_dumpctx_t *dctx) {
 	isc_event_t *event;
 
 	event = isc_event_allocate(dctx->mctx, NULL, DNS_EVENT_DUMPQUANTUM,
-				   dump_quantum, dctx, sizeof(*event));
+				   setup_dump, dctx, sizeof(*event));
 	isc_task_send(dctx->task, &event);
 	return (ISC_R_SUCCESS);
 }
@@ -1548,7 +1578,6 @@ dumpctx_create(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
 	dctx->done = NULL;
 	dctx->done_arg = NULL;
 	dctx->task = NULL;
-	dctx->nodes = 0;
 	dctx->first = true;
 	atomic_init(&dctx->canceled, false);
 	dctx->file = NULL;
@@ -1702,13 +1731,12 @@ writeheader(dns_dumpctx_t *dctx) {
 }
 
 static isc_result_t
-dumptostreaminc(dns_dumpctx_t *dctx) {
+dumptostream(dns_dumpctx_t *dctx) {
 	isc_result_t result = ISC_R_SUCCESS;
 	isc_buffer_t buffer;
 	char *bufmem;
 	dns_name_t *name;
 	dns_fixedname_t fixname;
-	unsigned int nodes;
 	isc_time_t start;
 
 	bufmem = isc_mem_get(dctx->mctx, initial_buffer_length);
@@ -1742,9 +1770,8 @@ dumptostreaminc(dns_dumpctx_t *dctx) {
 		result = ISC_R_SUCCESS;
 	}
 
-	nodes = dctx->nodes;
 	isc_time_now(&start);
-	while (result == ISC_R_SUCCESS && (dctx->nodes == 0 || nodes--)) {
+	while (result == ISC_R_SUCCESS) {
 		dns_rdatasetiter_t *rdsiter = NULL;
 		dns_dbnode_t *node = NULL;
 
@@ -1780,52 +1807,7 @@ dumptostreaminc(dns_dumpctx_t *dctx) {
 		result = dns_dbiterator_next(dctx->dbiter);
 	}
 
-	/*
-	 * Work out how many nodes can be written in the time between
-	 * two requests to the nameserver.  Smooth the resulting number and
-	 * use it as a estimate for the number of nodes to be written in the
-	 * next iteration.
-	 */
-	if (dctx->nodes != 0 && result == ISC_R_SUCCESS) {
-		unsigned int pps = dns_pps; /* packets per second */
-		unsigned int interval;
-		uint64_t usecs;
-		isc_time_t end;
-
-		isc_time_now(&end);
-		if (pps < 100) {
-			pps = 100;
-		}
-		interval = 1000000 / pps; /* interval in usecs */
-		if (interval == 0) {
-			interval = 1;
-		}
-		usecs = isc_time_microdiff(&end, &start);
-		if (usecs == 0) {
-			dctx->nodes = dctx->nodes * 2;
-			if (dctx->nodes > 1000) {
-				dctx->nodes = 1000;
-			}
-		} else {
-			nodes = dctx->nodes * interval;
-			nodes /= (unsigned int)usecs;
-			if (nodes == 0) {
-				nodes = 1;
-			} else if (nodes > 1000) {
-				nodes = 1000;
-			}
-
-			/* Smooth and assign. */
-			dctx->nodes = (nodes + dctx->nodes * 7) / 8;
-
-			isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,
-				      DNS_LOGMODULE_MASTERDUMP,
-				      ISC_LOG_DEBUG(1),
-				      "dumptostreaminc(%p) new nodes -> %d",
-				      dctx, dctx->nodes);
-		}
-		result = DNS_R_CONTINUE;
-	} else if (result == ISC_R_NOMORE) {
+	if (result == ISC_R_NOMORE) {
 		result = ISC_R_SUCCESS;
 	}
 cleanup:
@@ -1835,11 +1817,11 @@ cleanup:
 }
 
 isc_result_t
-dns_master_dumptostreaminc(isc_mem_t *mctx, dns_db_t *db,
-			   dns_dbversion_t *version,
-			   const dns_master_style_t *style, FILE *f,
-			   isc_task_t *task, dns_dumpdonefunc_t done,
-			   void *done_arg, dns_dumpctx_t **dctxp) {
+dns_master_dumptostreamasync(isc_mem_t *mctx, dns_db_t *db,
+			     dns_dbversion_t *version,
+			     const dns_master_style_t *style, FILE *f,
+			     isc_task_t *task, dns_dumpdonefunc_t done,
+			     void *done_arg, dns_dumpctx_t **dctxp) {
 	dns_dumpctx_t *dctx = NULL;
 	isc_result_t result;
 
@@ -1855,7 +1837,6 @@ dns_master_dumptostreaminc(isc_mem_t *mctx, dns_db_t *db,
 	isc_task_attach(task, &dctx->task);
 	dctx->done = done;
 	dctx->done_arg = done_arg;
-	dctx->nodes = 100;
 
 	result = task_send(dctx);
 	if (result == ISC_R_SUCCESS) {
@@ -1881,7 +1862,7 @@ dns_master_dumptostream(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
 		return (result);
 	}
 
-	result = dumptostreaminc(dctx);
+	result = dumptostream(dctx);
 	INSIST(result != DNS_R_CONTINUE);
 	dns_dumpctx_detach(&dctx);
 
@@ -1917,6 +1898,11 @@ opentmp(isc_mem_t *mctx, dns_masterformat_t format, const char *file,
 			      isc_result_totext(result));
 		goto cleanup;
 	}
+
+#if defined(POSIX_FADV_DONTNEED)
+	posix_fadvise(fileno(f), 0, 0, POSIX_FADV_DONTNEED);
+#endif
+
 	*tempp = tempname;
 	*fp = f;
 	return (ISC_R_SUCCESS);
@@ -1927,11 +1913,11 @@ cleanup:
 }
 
 isc_result_t
-dns_master_dumpinc(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
-		   const dns_master_style_t *style, const char *filename,
-		   isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
-		   dns_dumpctx_t **dctxp, dns_masterformat_t format,
-		   dns_masterrawheader_t *header) {
+dns_master_dumpasync(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
+		     const dns_master_style_t *style, const char *filename,
+		     isc_task_t *task, dns_dumpdonefunc_t done, void *done_arg,
+		     dns_dumpctx_t **dctxp, dns_masterformat_t format,
+		     dns_masterrawheader_t *header) {
 	FILE *f = NULL;
 	isc_result_t result;
 	char *tempname = NULL;
@@ -1956,7 +1942,6 @@ dns_master_dumpinc(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
 	isc_task_attach(task, &dctx->task);
 	dctx->done = done;
 	dctx->done_arg = done_arg;
-	dctx->nodes = 100;
 	dctx->file = file;
 	file = NULL;
 	dctx->tmpfile = tempname;
@@ -2001,7 +1986,7 @@ dns_master_dump(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
 		goto cleanup;
 	}
 
-	result = dumptostreaminc(dctx);
+	result = dumptostream(dctx);
 	INSIST(result != DNS_R_CONTINUE);
 	dns_dumpctx_detach(&dctx);
 
diff --git a/lib/dns/win32/libdns.def.in b/lib/dns/win32/libdns.def.in
index ab01b696df..97208946ef 100644
--- a/lib/dns/win32/libdns.def.in
+++ b/lib/dns/win32/libdns.def.in
@@ -493,11 +493,11 @@ dns_lookup_cancel
 dns_lookup_create
 dns_lookup_destroy
 dns_master_dump
-dns_master_dumpinc
+dns_master_dumpasync
 dns_master_dumpnode
 dns_master_dumpnodetostream
 dns_master_dumptostream
-dns_master_dumptostreaminc
+dns_master_dumptostreamasync
 dns_master_initrawheader
 dns_master_loadbuffer
 dns_master_loadbufferinc
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 6424343613..c4788ea203 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -2549,7 +2549,7 @@ zone_gotwritehandle(isc_task_t *task, isc_event_t *event) {
 		} else {
 			output_style = &dns_master_style_default;
 		}
-		result = dns_master_dumpinc(
+		result = dns_master_dumpasync(
 			zone->mctx, db, version, output_style, zone->masterfile,
 			zone->task, dump_done, zone, &zone->dctx,
 			zone->masterformat, &rawdata);
diff --git a/lib/isc/include/isc/netmgr.h b/lib/isc/include/isc/netmgr.h
index ca40fc6bcd..b8f19bf15a 100644
--- a/lib/isc/include/isc/netmgr.h
+++ b/lib/isc/include/isc/netmgr.h
@@ -68,6 +68,12 @@ typedef void (*isc_nm_opaquecb_t)(void *arg);
  * callbacks.
  */
 
+typedef void (*isc_nm_workcb_t)(void *arg);
+typedef void (*isc_nm_after_workcb_t)(void *arg, isc_result_t result);
+/*%<
+ * Callback functions for libuv threadpool work (see uv_work_t)
+ */
+
 void
 isc_nm_attach(isc_nm_t *mgr, isc_nm_t **dst);
 void
@@ -529,6 +535,19 @@ isc_nm_task_enqueue(isc_nm_t *mgr, isc_task_t *task, int threadid);
  *     maximum number of 'workers' as specifed in isc_nm_start()
  */
 
+void
+isc_nm_work_offload(isc_nm_t *mgr, isc_nm_workcb_t work_cb,
+		    isc_nm_after_workcb_t after_work_cb, void *data);
+/*%<
+ * Schedules a job to be handled by the libuv thread pool (see uv_work_t).
+ * The function specified in `work_cb` will be run by a thread in the
+ * thread pool; when complete, the `after_work_cb` function will run.
+ *
+ * Requires:
+ * \li 'mgr' is a valid netmgr object.
+ * \li We are currently running in a network manager thread.
+ */
+
 void
 isc__nm_force_tid(int tid);
 /*%<
diff --git a/lib/isc/include/isc/task.h b/lib/isc/include/isc/task.h
index f1facae397..fc33330267 100644
--- a/lib/isc/include/isc/task.h
+++ b/lib/isc/include/isc/task.h
@@ -511,6 +511,9 @@ isc_task_getname(isc_task_t *task);
  *
  */
 
+isc_nm_t *
+isc_task_getnetmgr(isc_task_t *task);
+
 void *
 isc_task_gettag(isc_task_t *task);
 /*%<
diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index dece53bfec..9e5445664b 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -646,6 +646,17 @@ typedef union {
 	isc__netievent_tlsconnect_t nitc;
 } isc__netievent_storage_t;
 
+/*
+ * Work item for a uv_work threadpool.
+ */
+typedef struct isc__nm_work {
+	isc_nm_t *netmgr;
+	uv_work_t req;
+	isc_nm_workcb_t cb;
+	isc_nm_after_workcb_t after_cb;
+	void *data;
+} isc__nm_work_t;
+
 /*
  * Network manager
  */
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 9692be6a4b..0b708b57d5 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -40,6 +40,7 @@
 #include "netmgr-int.h"
 #include "netmgr_p.h"
 #include "openssl_shim.h"
+#include "trampoline_p.h"
 #include "uv-compat.h"
 
 /*%
@@ -199,6 +200,14 @@ static void
 isc__nm_async_detach(isc__networker_t *worker, isc__netievent_t *ev0);
 static void
 isc__nm_async_close(isc__networker_t *worker, isc__netievent_t *ev0);
+
+static void
+isc__nm_threadpool_initialize(uint32_t workers);
+static void
+isc__nm_work_cb(uv_work_t *req);
+static void
+isc__nm_after_work_cb(uv_work_t *req, int status);
+
 /*%<
  * Issue a 'handle closed' callback on the socket.
  */
@@ -256,6 +265,17 @@ isc__nm_winsock_destroy(void) {
 }
 #endif /* WIN32 */
 
+static void
+isc__nm_threadpool_initialize(uint32_t workers) {
+	char buf[11];
+	int r = uv_os_getenv("UV_THREADPOOL_SIZE", buf,
+			     &(size_t){ sizeof(buf) });
+	if (r == UV_ENOENT) {
+		snprintf(buf, sizeof(buf), "%" PRIu32, workers);
+		uv_os_setenv("UV_THREADPOOL_SIZE", buf);
+	}
+}
+
 void
 isc__netmgr_create(isc_mem_t *mctx, uint32_t workers, isc_nm_t **netmgrp) {
 	isc_nm_t *mgr = NULL;
@@ -267,6 +287,8 @@ isc__netmgr_create(isc_mem_t *mctx, uint32_t workers, isc_nm_t **netmgrp) {
 	isc__nm_winsock_initialize();
 #endif /* WIN32 */
 
+	isc__nm_threadpool_initialize(workers);
+
 	mgr = isc_mem_get(mctx, sizeof(*mgr));
 	*mgr = (isc_nm_t){ .nworkers = workers };
 
@@ -280,8 +302,6 @@ isc__netmgr_create(isc_mem_t *mctx, uint32_t workers, isc_nm_t **netmgrp) {
 	atomic_init(&mgr->workers_paused, 0);
 	atomic_init(&mgr->paused, false);
 	atomic_init(&mgr->closing, false);
-	atomic_init(&mgr->idle, false);
-	atomic_init(&mgr->keepalive, false);
 	atomic_init(&mgr->recv_tcp_buffer_size, 0);
 	atomic_init(&mgr->send_tcp_buffer_size, 0);
 	atomic_init(&mgr->recv_udp_buffer_size, 0);
@@ -818,7 +838,8 @@ async_cb(uv_async_t *handle) {
 	isc__networker_t *worker = (isc__networker_t *)handle->loop->data;
 
 	if (process_all_queues(worker)) {
-		/* If we didn't process all the events, we need to enqueue
+		/*
+		 * If we didn't process all the events, we need to enqueue
 		 * async_cb to be run in the next iteration of the uv_loop
 		 */
 		uv_async_send(handle);
@@ -3242,6 +3263,73 @@ isc__nm_set_network_buffers(isc_nm_t *nm, uv_handle_t *handle) {
 	}
 }
 
+static isc_threadresult_t
+isc__nm_work_run(isc_threadarg_t arg) {
+	isc__nm_work_t *work = (isc__nm_work_t *)arg;
+
+	work->cb(work->data);
+
+	return ((isc_threadresult_t)0);
+}
+
+static void
+isc__nm_work_cb(uv_work_t *req) {
+	isc__nm_work_t *work = uv_req_get_data((uv_req_t *)req);
+
+	if (isc_tid_v == SIZE_MAX) {
+		isc__trampoline_t *trampoline_arg =
+			isc__trampoline_get(isc__nm_work_run, work);
+		(void)isc__trampoline_run(trampoline_arg);
+	} else {
+		(void)isc__nm_work_run((isc_threadarg_t)work);
+	}
+}
+
+static void
+isc__nm_after_work_cb(uv_work_t *req, int status) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc__nm_work_t *work = uv_req_get_data((uv_req_t *)req);
+	isc_nm_t *netmgr = work->netmgr;
+
+	if (status != 0) {
+		result = isc__nm_uverr2result(status);
+	}
+
+	work->after_cb(work->data, result);
+
+	isc_mem_put(netmgr->mctx, work, sizeof(*work));
+
+	isc_nm_detach(&netmgr);
+}
+
+void
+isc_nm_work_offload(isc_nm_t *netmgr, isc_nm_workcb_t work_cb,
+		    isc_nm_after_workcb_t after_work_cb, void *data) {
+	isc__networker_t *worker = NULL;
+	isc__nm_work_t *work = NULL;
+	int r;
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(VALID_NM(netmgr));
+
+	worker = &netmgr->workers[isc_nm_tid()];
+
+	work = isc_mem_get(netmgr->mctx, sizeof(*work));
+	*work = (isc__nm_work_t){
+		.cb = work_cb,
+		.after_cb = after_work_cb,
+		.data = data,
+	};
+
+	isc_nm_attach(netmgr, &work->netmgr);
+
+	uv_req_set_data((uv_req_t *)&work->req, work);
+
+	r = uv_queue_work(&worker->loop, &work->req, isc__nm_work_cb,
+			  isc__nm_after_work_cb);
+	RUNTIME_CHECK(r == 0);
+}
+
 #ifdef NETMGR_TRACE
 /*
  * Dump all active sockets in netmgr. We output to stderr
@@ -3302,7 +3390,8 @@ nmsocket_dump(isc_nmsocket_t *sock) {
 		nmsocket_type_totext(sock->type),
 		isc_refcount_current(&sock->references));
 	fprintf(stderr,
-		"Parent %p, listener %p, server %p, statichandle = %p\n",
+		"Parent %p, listener %p, server %p, statichandle = "
+		"%p\n",
 		sock->parent, sock->listener, sock->server, sock->statichandle);
 	fprintf(stderr, "Flags:%s%s%s%s%s\n",
 		atomic_load(&sock->active) ? " active" : "",
diff --git a/lib/isc/netmgr/uv-compat.c b/lib/isc/netmgr/uv-compat.c
index a0e1add2d7..89d7ac025c 100644
--- a/lib/isc/netmgr/uv-compat.c
+++ b/lib/isc/netmgr/uv-compat.c
@@ -16,7 +16,7 @@
 
 #include "netmgr-int.h"
 
-#ifndef HAVE_UV_UDP_CONNECT
+#if UV_VERSION_HEX < UV_VERSION(1, 27, 0)
 int
 isc_uv_udp_connect(uv_udp_t *handle, const struct sockaddr *addr) {
 	int err = 0;
@@ -46,7 +46,7 @@ isc_uv_udp_connect(uv_udp_t *handle, const struct sockaddr *addr) {
 
 	return (0);
 }
-#endif /* ifndef HAVE_UV_UDP_CONNECT */
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 27, 0) */
 
 int
 isc_uv_udp_freebind(uv_udp_t *handle, const struct sockaddr *addr,
diff --git a/lib/isc/netmgr/uv-compat.h b/lib/isc/netmgr/uv-compat.h
index 8cd4b160f5..c7037353f5 100644
--- a/lib/isc/netmgr/uv-compat.h
+++ b/lib/isc/netmgr/uv-compat.h
@@ -19,28 +19,35 @@
  * library version.
  */
 
-#ifndef HAVE_UV_HANDLE_GET_DATA
+#define UV_VERSION(major, minor, patch) ((major << 16) | (minor << 8) | (patch))
+
+#if UV_VERSION_HEX < UV_VERSION(1, 19, 0)
 static inline void *
 uv_handle_get_data(const uv_handle_t *handle) {
 	return (handle->data);
 }
-#endif /* ifndef HAVE_UV_HANDLE_GET_DATA */
 
-#ifndef HAVE_UV_HANDLE_SET_DATA
 static inline void
 uv_handle_set_data(uv_handle_t *handle, void *data) {
 	handle->data = data;
 }
-#endif /* ifndef HAVE_UV_HANDLE_SET_DATA */
 
-#ifndef HAVE_UV_SLEEP
+static inline void *
+uv_req_get_data(const uv_req_t *req) {
+	return (req->data);
+}
+
+static inline void
+uv_req_set_data(uv_req_t *req, void *data) {
+	req->data = data;
+}
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 19, 0) */
+
+#if UV_VERSION_HEX < UV_VERSION(1, 34, 0)
 #define uv_sleep(msec) usleep(msec * 1000)
-#endif
-
-#ifdef HAVE_UV_UDP_CONNECT
-#define isc_uv_udp_connect uv_udp_connect
-#else
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 34, 0) */
 
+#if UV_VERSION_HEX < UV_VERSION(1, 27, 0)
 int
 isc_uv_udp_connect(uv_udp_t *handle, const struct sockaddr *addr);
 /*%<
@@ -50,8 +57,37 @@ isc_uv_udp_connect(uv_udp_t *handle, const struct sockaddr *addr);
  * NOTE: This is just a limited shim for uv_udp_connect() as it requires the
  * handle to be bound.
  */
+#else /* UV_VERSION_HEX < UV_VERSION(1, 27, 0) */
+#define isc_uv_udp_connect uv_udp_connect
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 27, 0) */
 
-#endif
+#if UV_VERSION_HEX < UV_VERSION(1, 12, 0)
+#include <stdlib.h>
+#include <string.h>
+
+static inline int
+uv_os_getenv(const char *name, char *buffer, size_t *size) {
+	size_t len;
+	char *buf = getenv(name);
+
+	if (buf == NULL) {
+		return (UV_ENOENT);
+	}
+
+	len = strlen(buf) + 1;
+	if (len > *size) {
+		*size = len;
+		return (UV_ENOBUFS);
+	}
+
+	*size = len;
+	memmove(buffer, buf, len);
+
+	return (0);
+}
+
+#define uv_os_setenv(name, value) setenv(name, value, 0)
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 12, 0) */
 
 int
 isc_uv_udp_freebind(uv_udp_t *handle, const struct sockaddr *addr,
diff --git a/lib/isc/task.c b/lib/isc/task.c
index c85ac76197..e93c5d5856 100644
--- a/lib/isc/task.c
+++ b/lib/isc/task.c
@@ -774,6 +774,13 @@ isc_task_gettag(isc_task_t *task) {
 	return (task->tag);
 }
 
+isc_nm_t *
+isc_task_getnetmgr(isc_task_t *task) {
+	REQUIRE(VALID_TASK(task));
+
+	return (task->manager->netmgr);
+}
+
 /***
  *** Task Manager.
  ***/
diff --git a/lib/isc/win32/libisc.def.in b/lib/isc/win32/libisc.def.in
index fdf402a572..743d2cf6b8 100644
--- a/lib/isc/win32/libisc.def.in
+++ b/lib/isc/win32/libisc.def.in
@@ -100,6 +100,7 @@ isc_socketmgr_getmaxsockets
 isc_socketmgr_setreserved
 isc_socketmgr_setstats
 isc_task_getname
+isc_task_getnetmgr
 isc_task_gettag
 isc_task_ready
 isc_task_run
@@ -474,11 +475,13 @@ isc_nm_tcpdnsconnect
 isc_nm_gettimeouts
 isc_nm_setnetbuffers
 isc_nm_settimeouts
+isc_nm_task_enqueue
 isc_nm_tcpdns_keepalive
 isc_nm_tcpdns_sequential
 isc_nm_tid
 isc_nm_tlsdnsconnect
 isc_nm_udpconnect
+isc_nm_work_offload
 isc_nmsocket_close
 isc__nm_acquire_interlocked
 isc__nm_drop_interlocked
diff --git a/util/copyrights b/util/copyrights
index 22a6cbc908..9e4beecd80 100644
--- a/util/copyrights
+++ b/util/copyrights
@@ -2260,4 +2260,3 @@
 ./win32utils/Configure				PERL	2013,2014,2015,2016,2017,2018,2019,2020,2021
 ./win32utils/GeoIP.diff				X	2013,2018,2019,2020,2021
 ./win32utils/bind9.sln.in			X	2013,2014,2015,2016,2017,2018,2019,2020
-./win32utils/libuv.diff				X	2020,2021
diff --git a/win32utils/Configure b/win32utils/Configure
index c5870ea78a..c3903f0a84 100644
--- a/win32utils/Configure
+++ b/win32utils/Configure
@@ -172,9 +172,6 @@ my @substdefh = ("PACKAGE_VERSION_MAJOR",
                  "WITH_IDN",
                  "CPU_RELAX",
                  "VALIDATION_DEFAULT",
-                 "HAVE_UV_HANDLE_GET_DATA",
-                 "HAVE_UV_HANDLE_SET_DATA",
-                 "HAVE_UV_IMPORT",
     );
 
 # for platform.h
@@ -1276,13 +1273,6 @@ if ($use_libuv eq "auto") {
     if ($use_libuv eq "auto") {
         die "can't find an libuv built directory at sibling root\n";
     }
-
-    # When a libuv version exposing uv_import() and uv_export() is released, the
-    # following three config.h macros will need to be conditionally defined for
-    # that libuv version and all later ones.
-    # $configdefh{"HAVE_UV_HANDLE_SET_DATA"} = 1;
-    # $configdefh{"HAVE_UV_HANDLE_GET_DATA"} = 1;
-    # $configdefh{"HAVE_UV_IMPORT"} = 1;
 }
 # falls into (so no else)
 if ($use_libuv eq "yes") {
@@ -1309,12 +1299,6 @@ if ($use_libuv eq "yes") {
     $configinc{"LIBUV_INC"} = "$libuv_inc";
     $configlib{"LIBUV_LIB"} = "$libuv_lib";
     $configdll{"LIBUV_DLL"} = "$libuv_dll";
-    # When a libuv version exposing uv_import() and uv_export() is released, the
-    # following three config.h macros will need to be conditionally defined for
-    # that libuv version and all later ones.
-    # $configdefh{"HAVE_UV_HANDLE_SET_DATA"} = 1;
-    # $configdefh{"HAVE_UV_HANDLE_GET_DATA"} = 1;
-    # $configdefh{"HAVE_UV_IMPORT"} = 1;
 }
 
 # with-nghttp2
diff --git a/win32utils/libuv.diff b/win32utils/libuv.diff
deleted file mode 100644
index 41f3796ccc..0000000000
--- a/win32utils/libuv.diff
+++ /dev/null
@@ -1,27 +0,0 @@
-To make TCP listening properly multithreaded, we need to have the
-uv_export() and uv_import() functions that were removed from libuv.
-The alternative is passing sockets over IPC, which is complicated and
-error prone.
-
-To make it simple, we export two internal functions from libuv; they will
-be used in lib/isc/netmgr/uv-compat.c by our versions of the uv_export()
-and uv_import() functions.
-
-diff --git a/src/win/internal.h b/src/win/internal.h
-index 058ddb8e..a9dc4168 100644
---- a/src/win/internal.h
-+++ b/src/win/internal.h
-@@ -92,11 +92,11 @@ void uv_process_tcp_connect_req(uv_loop_t* loop, uv_tcp_t* handle,
- void uv_tcp_close(uv_loop_t* loop, uv_tcp_t* tcp);
- void uv_tcp_endgame(uv_loop_t* loop, uv_tcp_t* handle);
- 
--int uv__tcp_xfer_export(uv_tcp_t* handle,
-+UV_EXTERN int uv__tcp_xfer_export(uv_tcp_t* handle,
-                         int pid,
-                         uv__ipc_socket_xfer_type_t* xfer_type,
-                         uv__ipc_socket_xfer_info_t* xfer_info);
--int uv__tcp_xfer_import(uv_tcp_t* tcp,
-+UV_EXTERN int uv__tcp_xfer_import(uv_tcp_t* tcp,
-                         uv__ipc_socket_xfer_type_t xfer_type,
-                         uv__ipc_socket_xfer_info_t* xfer_info);
-