diff --git a/candm.h b/candm.h
index 2d66997..e0d5140 100644
--- a/candm.h
+++ b/candm.h
@@ -103,7 +103,8 @@
 #define REQ_ONOFFLINE 63
 #define REQ_ADD_SOURCE 64
 #define REQ_NTP_SOURCE_NAME 65
-#define N_REQUEST_TYPES 66
+#define REQ_RESET 66
+#define N_REQUEST_TYPES 67
 
 /* Structure used to exchange timespecs independent of time_t size */
 typedef struct {
diff --git a/client.c b/client.c
index de08be2..6f0aad2 100644
--- a/client.c
+++ b/client.c
@@ -1269,6 +1269,7 @@ give_help(void)
     "cyclelogs\0Close and re-open log files\0"
     "dump\0Dump all measurements to save files\0"
     "rekey\0Re-read keys from key file\0"
+    "reset\0Drop all measurements\0"
     "shutdown\0Stop daemon\0"
     "\0\0"
     "Client commands:\0\0"
@@ -1315,7 +1316,7 @@ command_name_generator(const char *text, int state)
     "deny", "dns", "dump", "exit", "help", "keygen", "local", "makestep",
     "manual", "maxdelay", "maxdelaydevratio", "maxdelayratio", "maxpoll",
     "maxupdateskew", "minpoll", "minstratum", "ntpdata", "offline", "online", "onoffline",
-    "polltarget", "quit", "refresh", "rekey", "reselect", "reselectdist",
+    "polltarget", "quit", "refresh", "rekey", "reselect", "reselectdist", "reset",
     "retries", "rtcdata", "serverstats", "settime", "shutdown", "smoothing",
     "smoothtime", "sourcename", "sources", "sourcestats",
     "timeout", "tracking", "trimrtc", "waitsync", "writertc",
@@ -2835,6 +2836,14 @@ process_cmd_shutdown(CMD_Request *msg, char *line)
 
 /* ================================================== */
 
+static void
+process_cmd_reset(CMD_Request *msg, char *line)
+{
+  msg->command = htons(REQ_RESET);
+}
+
+/* ================================================== */
+
 static int
 process_cmd_waitsync(char *line)
 {
@@ -3129,6 +3138,8 @@ process_line(char *line)
     process_cmd_reselect(&tx_message, line);
   } else if (!strcmp(command, "reselectdist")) {
     do_normal_submit = process_cmd_reselectdist(&tx_message, line);
+  } else if (!strcmp(command, "reset")) {
+    process_cmd_reset(&tx_message, line);
   } else if (!strcmp(command, "retries")) {
     ret = process_cmd_retries(line);
     do_normal_submit = 0;
diff --git a/cmdmon.c b/cmdmon.c
index 7950e7a..908977e 100644
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -134,6 +134,7 @@ static const char permissions[] = {
   PERMIT_AUTH, /* ONOFFLINE */
   PERMIT_AUTH, /* ADD_SOURCE */
   PERMIT_OPEN, /* NTP_SOURCE_NAME */
+  PERMIT_AUTH, /* RESET */
 };
 
 /* ================================================== */
@@ -1218,6 +1219,18 @@ handle_ntp_source_name(CMD_Request *rx_message, CMD_Reply *tx_message)
             sizeof (tx_message->data.ntp_source_name.name));
 }
 
+/* ================================================== */
+
+static void
+handle_reset(CMD_Request *rx_message, CMD_Reply *tx_message)
+{
+  struct timespec cooked_now, now;
+
+  SRC_ResetSources();
+  SCH_GetLastEventTime(&cooked_now, NULL, &now);
+  LCL_NotifyExternalTimeStep(&now, &cooked_now, 0.0, 0.0);
+}
+
 /* ================================================== */
 /* Read a packet and process it */
 
@@ -1595,6 +1608,10 @@ read_from_cmd_socket(int sock_fd, int event, void *anything)
           handle_ntp_source_name(&rx_message, &tx_message);
           break;
 
+        case REQ_RESET:
+          handle_reset(&rx_message, &tx_message);
+          break;
+
         default:
           DEBUG_LOG("Unhandled command %d", rx_command);
           tx_message.status = htons(STT_FAILED);
diff --git a/doc/chronyc.adoc b/doc/chronyc.adoc
index 2a99a16..e97c66f 100644
--- a/doc/chronyc.adoc
+++ b/doc/chronyc.adoc
@@ -1171,6 +1171,13 @@ running.
 The *rekey* command causes *chronyd* to re-read the key file specified in the
 configuration file by the <<chrony.conf.adoc#keyfile,*keyfile*>> directive.
 
+[[reset]]*reset*::
+The *reset* command causes *chronyd* to drop all measurements and switch to the
+unsynchronised state. This command can help *chronyd* with recovery when the
+measurements are known to be no longer valid or accurate, e.g. due to moving
+the computer to a different network, or resuming the computer from a low-power
+state (which resets the system clock).
+
 [[shutdown]]*shutdown*::
 The *shutdown* command causes *chronyd* to exit. This is equivalent to sending
 the process the SIGTERM signal.
diff --git a/pktlength.c b/pktlength.c
index 32b6f5a..911f725 100644
--- a/pktlength.c
+++ b/pktlength.c
@@ -123,6 +123,7 @@ static const struct request_length request_lengths[] = {
   REQ_LENGTH_ENTRY(ntp_source, null),           /* ADD_SOURCE */
   REQ_LENGTH_ENTRY(ntp_source_name,
                    ntp_source_name),            /* NTP_SOURCE_NAME */
+  REQ_LENGTH_ENTRY(null, null),                 /* RESET */
 };
 
 static const uint16_t reply_lengths[] = {
diff --git a/sources.c b/sources.c
index b440d9d..2db0299 100644
--- a/sources.c
+++ b/sources.c
@@ -1252,6 +1252,17 @@ SRC_RemoveDumpFiles(void)
 
 /* ================================================== */
 
+void
+SRC_ResetSources(void)
+{
+  int i;
+
+  for (i = 0; i < n_sources; i++)
+    SRC_ResetInstance(sources[i]);
+}
+
+/* ================================================== */
+
 int
 SRC_IsSyncPeer(SRC_Instance inst)
 {
diff --git a/sources.h b/sources.h
index c160029..75f0f23 100644
--- a/sources.h
+++ b/sources.h
@@ -114,6 +114,8 @@ extern void SRC_DumpSources(void);
 extern void SRC_ReloadSources(void);
 extern void SRC_RemoveDumpFiles(void);
 
+extern void SRC_ResetSources(void);
+
 extern int SRC_IsSyncPeer(SRC_Instance inst);
 extern int SRC_IsReachable(SRC_Instance inst);
 extern int SRC_ReadNumberOfSources(void);
diff --git a/test/simulation/110-chronyc b/test/simulation/110-chronyc
index bc6b232..e20cf3d 100755
--- a/test/simulation/110-chronyc
+++ b/test/simulation/110-chronyc
@@ -138,6 +138,7 @@ for chronyc_conf in \
 	"rekey" \
 	"reselect" \
 	"reselectdist 1e-3" \
+	"reset" \
 	"settime 16:30" \
 	"settime 16:30:05" \
 	"settime Nov 21, 2015 16:30:05" \