diff --git a/cmdmon.c b/cmdmon.c
index 9adc9d6..d2199a7 100644
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -789,7 +789,7 @@ handle_add_source(CMD_Request *rx_message, CMD_Reply *tx_message)
                       NTP_EF_FLAG_EXP_NET_CORRECTION : 0);
   params.sel_options = convert_addsrc_select_options(ntohl(rx_message->data.ntp_source.flags));
 
-  status = NSR_AddSourceByName(name, port, pool, type, &params, NULL);
+  status = NSR_AddSourceByName(name, IPADDR_UNSPEC, port, pool, type, &params, NULL);
   switch (status) {
     case NSR_Success:
       break;
diff --git a/conf.c b/conf.c
index fa74459..9bae265 100644
--- a/conf.c
+++ b/conf.c
@@ -1728,8 +1728,9 @@ reload_source_dirs(void)
       /* Add new sources */
       if (pass == 1 && d > 0) {
         source = &new_sources[j];
-        s = NSR_AddSourceByName(source->params.name, source->params.port, source->pool,
-                                source->type, &source->params.params, &new_ids[j]);
+        s = NSR_AddSourceByName(source->params.name, IPADDR_UNSPEC, source->params.port,
+                                source->pool, source->type, &source->params.params,
+                                &new_ids[j]);
 
         if (s == NSR_UnresolvedName) {
           unresolved++;
@@ -1842,8 +1843,8 @@ CNF_AddSources(void)
   for (i = 0; i < ARR_GetSize(ntp_sources); i++) {
     source = (NTP_Source *)ARR_GetElement(ntp_sources, i);
 
-    s = NSR_AddSourceByName(source->params.name, source->params.port, source->pool,
-                            source->type, &source->params.params, NULL);
+    s = NSR_AddSourceByName(source->params.name, IPADDR_UNSPEC, source->params.port,
+                            source->pool, source->type, &source->params.params, NULL);
     if (s != NSR_Success && s != NSR_UnresolvedName)
       LOG(LOGS_ERR, "Could not add source %s", source->params.name);
 
diff --git a/ntp_sources.c b/ntp_sources.c
index d8bd2d8..590e5e0 100644
--- a/ntp_sources.c
+++ b/ntp_sources.c
@@ -61,6 +61,8 @@ typedef struct {
                                    (may be an IP address) */
   IPAddr resolved_addr;         /* Address resolved from the name, which can be
                                    different from remote_addr (e.g. NTS-KE) */
+  int family;                   /* IP family of acceptable resolved addresses
+                                   (IPADDR_UNSPEC if any) */
   int pool_id;                  /* ID of the pool from which was this source
                                    added or INVALID_POOL */
   int tentative;                /* Flag indicating there was no valid response
@@ -98,6 +100,8 @@ struct UnresolvedSource {
   int pool_id;
   /* Name to be resolved */
   char *name;
+  /* Address family to filter resolved addresses */
+  int family;
   /* Flag indicating addresses should be used in a random order */
   int random_order;
   /* Flag indicating current address should be replaced only if it is
@@ -353,7 +357,7 @@ log_source(SourceRecord *record, int addition, int once_per_pool)
 
 /* Procedure to add a new source */
 static NSR_Status
-add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type,
+add_source(NTP_Remote_Address *remote_addr, char *name, int family, NTP_Source_Type type,
            SourceParameters *params, int pool_id, uint32_t conf_id)
 {
   SourceRecord *record;
@@ -391,6 +395,7 @@ add_source(NTP_Remote_Address *remote_addr, char *name, NTP_Source_Type type,
       record->data = NCR_CreateInstance(remote_addr, type, params, record->name);
       record->remote_addr = NCR_GetRemoteAddress(record->data);
       record->resolved_addr = remote_addr->ip_addr;
+      record->family = family;
       record->pool_id = pool_id;
       record->tentative = 1;
       record->conf_id = conf_id;
@@ -552,6 +557,10 @@ process_resolved_name(struct UnresolvedSource *us, IPAddr *ip_addrs, int n_addrs
 
     DEBUG_LOG("(%d) %s", i + 1, UTI_IPToString(&new_addr.ip_addr));
 
+    /* Skip addresses not from the requested family */
+    if (us->family != IPADDR_UNSPEC && us->family != new_addr.ip_addr.family)
+      continue;
+
     if (us->pool_id != INVALID_POOL) {
       /* In the pool resolving mode, try to replace a source from
          the pool which does not have a real address yet */
@@ -768,14 +777,14 @@ NSR_Status
 NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type type,
               SourceParameters *params, uint32_t *conf_id)
 {
-  return add_source(remote_addr, NULL, type, params, INVALID_POOL,
+  return add_source(remote_addr, NULL, IPADDR_UNSPEC, type, params, INVALID_POOL,
                     get_next_conf_id(conf_id));
 }
 
 /* ================================================== */
 
 NSR_Status
-NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
+NSR_AddSourceByName(char *name, int family, int port, int pool, NTP_Source_Type type,
                     SourceParameters *params, uint32_t *conf_id)
 {
   struct UnresolvedSource *us;
@@ -787,7 +796,9 @@ NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
   /* If the name is an IP address, add the source with the address directly */
   if (UTI_StringToIP(name, &remote_addr.ip_addr)) {
     remote_addr.port = port;
-    return add_source(&remote_addr, name, type, params, INVALID_POOL,
+    if (family != IPADDR_UNSPEC && family != remote_addr.ip_addr.family)
+      return NSR_InvalidAF;
+    return add_source(&remote_addr, name, IPADDR_UNSPEC, type, params, INVALID_POOL,
                       get_next_conf_id(conf_id));
   }
 
@@ -799,6 +810,7 @@ NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
 
   us = MallocNew(struct UnresolvedSource);
   us->name = Strdup(name);
+  us->family = family;
   us->random_order = 0;
   us->refreshment = 0;
 
@@ -835,7 +847,7 @@ NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
   for (i = 0; i < new_sources; i++) {
     if (i > 0)
       remote_addr.ip_addr.addr.id = ++last_address_id;
-    if (add_source(&remote_addr, name, type, params, us->pool_id, cid) != NSR_Success)
+    if (add_source(&remote_addr, name, family, type, params, us->pool_id, cid) != NSR_Success)
       return NSR_TooManySources;
   }
 
@@ -1026,6 +1038,7 @@ resolve_source_replacement(SourceRecord *record, int refreshment)
 
   us = MallocNew(struct UnresolvedSource);
   us->name = Strdup(record->name);
+  us->family = record->family;
   /* Ignore the order of addresses from the resolver to not get
      stuck with a pair of unreachable or otherwise unusable servers
      (e.g. falsetickers) in case the order doesn't change, or a group
diff --git a/ntp_sources.h b/ntp_sources.h
index 5aeb1a3..79daf1d 100644
--- a/ntp_sources.h
+++ b/ntp_sources.h
@@ -55,9 +55,12 @@ extern NSR_Status NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type
 
 /* Procedure to add a new server, peer source, or pool of servers specified by
    name instead of address.  The name is resolved in exponentially increasing
-   intervals until it succeeds or fails with a non-temporary error.  If the
-   name is an address, it is equivalent to NSR_AddSource(). */
-extern NSR_Status NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
+   intervals until it succeeds or fails with a non-temporary error.  The
+   specified family filters resolved addresses.  If the name is an address
+   and its family does not conflict with the specified family, it is equivalent
+   to NSR_AddSource(). */
+extern NSR_Status NSR_AddSourceByName(char *name, int family, int port, int pool,
+                                      NTP_Source_Type type,
                                       SourceParameters *params, uint32_t *conf_id);
 
 extern const char *NSR_StatusToString(NSR_Status status);
diff --git a/stubs.c b/stubs.c
index b729c2f..044d17e 100644
--- a/stubs.c
+++ b/stubs.c
@@ -201,7 +201,7 @@ NSR_AddSource(NTP_Remote_Address *remote_addr, NTP_Source_Type type,
 }
 
 NSR_Status
-NSR_AddSourceByName(char *name, int port, int pool, NTP_Source_Type type,
+NSR_AddSourceByName(char *name, int family, int port, int pool, NTP_Source_Type type,
                     SourceParameters *params, uint32_t *conf_id)
 {
   return NSR_TooManySources;
diff --git a/test/unit/ntp_sources.c b/test/unit/ntp_sources.c
index e3d7c4d..a9bdbad 100644
--- a/test/unit/ntp_sources.c
+++ b/test/unit/ntp_sources.c
@@ -125,7 +125,7 @@ void
 test_unit(void)
 {
   char source_line[] = "127.0.0.1 offline", conf[] = "port 0", name[64];
-  int i, j, k, slot, found, pool, prev_n;
+  int i, j, k, family, slot, found, pool, prev_n;
   uint32_t hash = 0, conf_id;
   NTP_Remote_Address addrs[256], addr;
   NTP_Local_Address local_addr;
@@ -216,7 +216,7 @@ test_unit(void)
 
   TEST_CHECK(n_sources == 0);
 
-  status = NSR_AddSourceByName("a b", 0, 0, 0, &source.params, &conf_id);
+  status = NSR_AddSourceByName("a b", IPADDR_UNSPEC, 0, 0, 0, &source.params, &conf_id);
   TEST_CHECK(status == NSR_InvalidName);
 
   local_addr.ip_addr.family = IPADDR_INET4;
@@ -228,11 +228,13 @@ test_unit(void)
   for (i = 0; i < 500; i++) {
     for (j = 0; j < 20; j++) {
       snprintf(name, sizeof (name), "ntp%d.example.net", (int)(random() % 10));
+      family = random() % 2 ? IPADDR_UNSPEC : random() % 2 ? IPADDR_INET4 : IPADDR_INET6;
       pool = random() % 2;
       prev_n = n_sources;
 
       DEBUG_LOG("%d/%d adding source %s pool=%d", i, j, name, pool);
-      status = NSR_AddSourceByName(name, 0, pool, random() % 2 ? NTP_SERVER : NTP_PEER,
+      status = NSR_AddSourceByName(name, family, 0, pool,
+                                   random() % 2 ? NTP_SERVER : NTP_PEER,
                                    &source.params, &conf_id);
       TEST_CHECK(status == NSR_UnresolvedName);
 
@@ -242,11 +244,13 @@ test_unit(void)
       for (us = unresolved_sources; us->next; us = us->next)
         ;
       TEST_CHECK(strcmp(us->name, name) == 0);
+      TEST_CHECK(us->family == family);
       if (pool) {
         TEST_CHECK(us->address.ip_addr.family == IPADDR_UNSPEC && us->pool_id >= 0);
       } else {
         TEST_CHECK(strcmp(NSR_GetName(&us->address.ip_addr), name) == 0);
         TEST_CHECK(find_slot2(&us->address, &slot) == 2);
+        TEST_CHECK(get_record(slot)->family == family);
       }
 
       if (random() % 2) {