diff --git a/candm.h b/candm.h
index 033cdb9..5fe1222 100644
--- a/candm.h
+++ b/candm.h
@@ -279,6 +279,8 @@ typedef struct {
 #define REQ_ADDSRC_COPY 0x400
 #define REQ_ADDSRC_EF_EXP_MONO_ROOT 0x800
 #define REQ_ADDSRC_EF_EXP_NET_CORRECTION 0x1000
+#define REQ_ADDSRC_IPV4 0x2000
+#define REQ_ADDSRC_IPV6 0x4000
 
 typedef struct {
   uint32_t type;
diff --git a/client.c b/client.c
index 7cfefba..d5e3be7 100644
--- a/client.c
+++ b/client.c
@@ -962,6 +962,8 @@ process_cmd_add_source(CMD_Request *msg, char *line)
            REQ_ADDSRC_EF_EXP_MONO_ROOT : 0) |
           (data.params.ext_fields & NTP_EF_FLAG_EXP_NET_CORRECTION ?
            REQ_ADDSRC_EF_EXP_NET_CORRECTION : 0) |
+          (data.family == IPADDR_INET4 ? REQ_ADDSRC_IPV4 : 0) |
+          (data.family == IPADDR_INET6 ? REQ_ADDSRC_IPV6 : 0) |
           convert_addsrc_sel_options(data.params.sel_options));
       msg->data.ntp_source.filter_length = htonl(data.params.filter_length);
       msg->data.ntp_source.cert_set = htonl(data.params.cert_set);
diff --git a/cmdmon.c b/cmdmon.c
index 980c04e..c5b00a4 100644
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -720,10 +720,10 @@ handle_add_source(CMD_Request *rx_message, CMD_Reply *tx_message)
 {
   NTP_Source_Type type;
   SourceParameters params;
+  int family, pool, port;
   NSR_Status status;
   uint32_t flags;
   char *name;
-  int pool, port;
   
   switch (ntohl(rx_message->data.ntp_source.type)) {
     case REQ_ADDSRC_SERVER:
@@ -753,6 +753,8 @@ handle_add_source(CMD_Request *rx_message, CMD_Reply *tx_message)
 
   flags = ntohl(rx_message->data.ntp_source.flags);
 
+  family = flags & REQ_ADDSRC_IPV4 ? IPADDR_INET4 :
+           flags & REQ_ADDSRC_IPV6 ? IPADDR_INET6 : IPADDR_UNSPEC;
   port = ntohl(rx_message->data.ntp_source.port);
   params.minpoll = ntohl(rx_message->data.ntp_source.minpoll);
   params.maxpoll = ntohl(rx_message->data.ntp_source.maxpoll);
@@ -790,7 +792,7 @@ 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, IPADDR_UNSPEC, port, pool, type, &params, NULL);
+  status = NSR_AddSourceByName(name, family, port, pool, type, &params, NULL);
   switch (status) {
     case NSR_Success:
       break;
@@ -808,6 +810,8 @@ handle_add_source(CMD_Request *rx_message, CMD_Reply *tx_message)
       tx_message->status = htons(STT_INVALIDNAME);
       break;
     case NSR_InvalidAF:
+      tx_message->status = htons(STT_INVALIDAF);
+      break;
     case NSR_NoSuchSource:
       assert(0);
       break;
diff --git a/test/simulation/110-chronyc b/test/simulation/110-chronyc
index 46b0a3f..3cd1788 100755
--- a/test/simulation/110-chronyc
+++ b/test/simulation/110-chronyc
@@ -114,7 +114,7 @@ limit=1
 for chronyc_conf in \
 	"accheck 1.2.3.4" \
 	"add peer 10.0.0.0 minpoll 2 maxpoll 6" \
-	"add server 10.0.0.0 minpoll 6 maxpoll 10 iburst burst key 1 certset 2 maxdelay 1e-3 maxdelayratio 10.0 maxdelaydevratio 10.0 maxdelayquant 0.5 mindelay 1e-4 asymmetry 0.5 offset 1e-5 minsamples 6 maxsamples 6 filter 3 offline auto_offline prefer noselect trust require xleave polltarget 20 port 123 presend 7 minstratum 3 version 4 nts ntsport 4460 copy extfield F323 extfield F324" \
+	"add server 10.0.0.0 minpoll 6 maxpoll 10 iburst burst key 1 certset 2 maxdelay 1e-3 maxdelayratio 10.0 maxdelaydevratio 10.0 maxdelayquant 0.5 mindelay 1e-4 asymmetry 0.5 offset 1e-5 minsamples 6 maxsamples 6 filter 3 offline auto_offline prefer noselect trust require xleave polltarget 20 port 123 presend 7 minstratum 3 version 4 nts ntsport 4460 copy extfield F323 extfield F324 ipv6 ipv4" \
 	"add server node1.net1.clk" \
 	"allow 1.2.3.4" \
 	"allow 1.2" \
@@ -433,7 +433,12 @@ server_conf="
 server 192.168.123.1
 noclientlog"
 
-commands=(
+check_config_h 'FEAT_IPV6 1' && commands=(
+	"add server ::1 ipv4" "^515 Invalid address family$"
+	) || commands=()
+
+commands+=(
+	"add server 192.168.123.1 ipv6" "^515 Invalid address family$"
 	"add server nosuchnode.net1.clk" "^Invalid host/IP address$"
 	"allow nosuchnode.net1.clk" "^Could not read address$"
 	"allow 192.168.123.0/2 4" "^Could not read address$"