diff --git a/channeld/channeld.c b/channeld/channeld.c
index 30ae01f84..6506ae0db 100644
--- a/channeld/channeld.c
+++ b/channeld/channeld.c
@@ -55,6 +55,7 @@
 #include <inttypes.h>
 #include <secp256k1.h>
 #include <stdio.h>
+#include <wire/gen_common_wire.h>
 #include <wire/gen_onion_wire.h>
 #include <wire/peer_wire.h>
 #include <wire/wire.h>
@@ -2911,6 +2912,21 @@ static void req_in(struct peer *peer, const u8 *msg)
 	case WIRE_CHANNEL_SEND_ERROR_REPLY:
 		break;
 	}
+
+	/* Now handle common messages. */
+	switch ((enum common_wire_type)t) {
+#if DEVELOPER
+	case WIRE_CUSTOMMSG_OUT:
+		/* TODO(cdecker) Add handling of custom messages. */
+		return;
+#else
+	case WIRE_CUSTOMMSG_OUT:
+#endif
+	/* We send these. */
+	case WIRE_CUSTOMMSG_IN:
+		break;
+	}
+
 	master_badmsg(-1, msg);
 }
 
diff --git a/lightningd/channel_control.c b/lightningd/channel_control.c
index f59d56795..9256151bf 100644
--- a/lightningd/channel_control.c
+++ b/lightningd/channel_control.c
@@ -23,6 +23,7 @@
 #include <lightningd/log.h>
 #include <lightningd/peer_control.h>
 #include <lightningd/subd.h>
+#include <wire/gen_common_wire.h>
 #include <wire/wire_sync.h>
 
 static void update_feerates(struct lightningd *ld, struct channel *channel)
@@ -319,6 +320,19 @@ static unsigned channel_msg(struct subd *sd, const u8 *msg, const int *fds)
 		break;
 	}
 
+	switch ((enum common_wire_type)t) {
+#if DEVELOPER
+	case WIRE_CUSTOMMSG_IN:
+		/* TODO(cdecker) Add handling of custom messages. */
+		break;
+#else
+	case WIRE_CUSTOMMSG_IN:
+#endif
+	/* We send these. */
+	case WIRE_CUSTOMMSG_OUT:
+		break;
+	}
+
 	return 0;
 }
 
diff --git a/lightningd/opening_control.c b/lightningd/opening_control.c
index 614293484..27919a75a 100644
--- a/lightningd/opening_control.c
+++ b/lightningd/opening_control.c
@@ -33,6 +33,7 @@
 #include <lightningd/plugin_hook.h>
 #include <lightningd/subd.h>
 #include <openingd/gen_opening_wire.h>
+#include <wire/gen_common_wire.h>
 #include <wire/wire.h>
 #include <wire/wire_sync.h>
 
@@ -922,6 +923,20 @@ static unsigned int openingd_msg(struct subd *openingd,
 	case WIRE_OPENING_DEV_MEMLEAK_REPLY:
 		break;
 	}
+
+	switch ((enum common_wire_type)t) {
+#if DEVELOPER
+	case WIRE_CUSTOMMSG_IN:
+		/* TODO(cdecker) Add handling of custom messages. */
+		return 0;
+#else
+	case WIRE_CUSTOMMSG_IN:
+#endif
+	/* We send these. */
+	case WIRE_CUSTOMMSG_OUT:
+		break;
+	}
+
 	log_broken(openingd->log, "Unexpected msg %s: %s",
 		   opening_wire_type_name(t), tal_hex(tmpctx, msg));
 	tal_free(openingd);
diff --git a/openingd/openingd.c b/openingd/openingd.c
index 3b9e5258e..380d56a22 100644
--- a/openingd/openingd.c
+++ b/openingd/openingd.c
@@ -47,6 +47,7 @@
 #include <secp256k1.h>
 #include <stdio.h>
 #include <wally_bip32.h>
+#include <wire/gen_common_wire.h>
 #include <wire/gen_peer_wire.h>
 #include <wire/peer_wire.h>
 #include <wire/wire.h>
@@ -1413,6 +1414,20 @@ static u8 *handle_master_in(struct state *state)
 		break;
 	}
 
+	/* Now handle common messages. */
+	switch ((enum common_wire_type)t) {
+#if DEVELOPER
+	case WIRE_CUSTOMMSG_OUT:
+		/* TODO(cdecker) Add handling of custom messages. */
+		return NULL;
+#else
+	case WIRE_CUSTOMMSG_OUT:
+#endif
+	/* We send these. */
+	case WIRE_CUSTOMMSG_IN:
+		break;
+	}
+
 	status_failed(STATUS_FAIL_MASTER_IO,
 		      "Unknown msg %s", tal_hex(tmpctx, msg));
 }
diff --git a/wire/Makefile b/wire/Makefile
index 8a0efb011..92bec190b 100644
--- a/wire/Makefile
+++ b/wire/Makefile
@@ -10,8 +10,8 @@ WIRE_HEADERS_NOGEN := wire/onion_defs.h		\
 		wire/wire.h			\
 		wire/wire_sync.h		\
 		wire/wire_io.h
-WIRE_GEN_HEADERS := wire/gen_peer_wire.h wire/gen_onion_wire.h
-WIRE_GEN_SRC := wire/gen_peer_wire.c
+WIRE_GEN_HEADERS := wire/gen_peer_wire.h wire/gen_onion_wire.h wire/gen_common_wire.h
+WIRE_GEN_SRC := wire/gen_peer_wire.c wire/gen_common_wire.c
 WIRE_GEN_ONION_SRC := wire/gen_onion_wire.c
 WIRE_SRC := wire/wire_sync.c			\
 		wire/wire_io.c			\
@@ -85,6 +85,13 @@ wire/gen_onion_wire.h: wire/gen_onion_wire_csv $(WIRE_BOLT_DEPS) wire/Makefile
 wire/gen_onion_wire.c: wire/gen_onion_wire_csv $(WIRE_BOLT_DEPS) wire/Makefile
 	$(BOLT_GEN) -s --expose-tlv-type=tlv_payload --page impl ${@:.c=.h} onion_type < $< > $@
 
+# Some messages that are common among all daemons
+wire/gen_common_wire.h: wire/common_wire_csv $(WIRE_BOLT_DEPS) wire/Makefile
+	$(BOLT_GEN) -s --page header $@ common_wire_type < $< > $@
+
+wire/gen_common_wire.c: wire/common_wire_csv $(WIRE_BOLT_DEPS) wire/Makefile
+	$(BOLT_GEN) -s --page impl ${@:.c=.h} common_wire_type < $< > $@
+
 check-source: $(WIRE_SRC:%=check-src-include-order/%) $(WIRE_HEADERS_NOGEN:%=check-hdr-include-order/%)
 
 check-source-bolt: $(WIRE_SRC:%=bolt-check/%) $(WIRE_HEADERS_NOGEN:%=bolt-check/%)
diff --git a/wire/common_wire_csv b/wire/common_wire_csv
new file mode 100644
index 000000000..7e607c806
--- /dev/null
+++ b/wire/common_wire_csv
@@ -0,0 +1,10 @@
+# A custom message that we got from a peer and don't know how to handle, so we
+# forward it to the master for further handling.
+msgtype,custommsg_in,1030
+msgdata,custommsg_in,msg_len,u16,
+msgdata,custommsg_in,msg,u8,msg_len
+
+# A custom message that the master tells us to send to the peer.
+msgtype,custommsg_out,1031
+msgdata,custommsg_out,msg_len,u16,
+msgdata,custommsg_out,msg,u8,msg_len