diff --git a/flow.c b/flow.c
index d05aa49..223d059 100644
--- a/flow.c
+++ b/flow.c
@@ -108,6 +108,31 @@ static const union flow *flow_new_entry; /* = NULL */
 /* Last time the flow timers ran */
 static struct timespec flow_timer_run;
 
+/** flowside_from_af() - Initialise flowside from addresses
+ * @side:	flowside to initialise
+ * @af:		Address family (AF_INET or AF_INET6)
+ * @eaddr:	Endpoint address (pointer to in_addr or in6_addr)
+ * @eport:	Endpoint port
+ * @faddr:	Forwarding address (pointer to in_addr or in6_addr)
+ * @fport:	Forwarding port
+ */
+static void flowside_from_af(struct flowside *side, sa_family_t af,
+			     const void *eaddr, in_port_t eport,
+			     const void *faddr, in_port_t fport)
+{
+	if (faddr)
+		inany_from_af(&side->faddr, af, faddr);
+	else
+		side->faddr = inany_any6;
+	side->fport = fport;
+
+	if (eaddr)
+		inany_from_af(&side->eaddr, af, eaddr);
+	else
+		side->eaddr = inany_any6;
+	side->eport = eport;
+}
+
 /** flow_log_ - Log flow-related message
  * @f:		flow the message is related to
  * @pri:	Log priority
@@ -140,6 +165,8 @@ void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
  */
 static void flow_set_state(struct flow_common *f, enum flow_state state)
 {
+	char estr[INANY_ADDRSTRLEN], fstr[INANY_ADDRSTRLEN];
+	const struct flowside *ini = &f->side[INISIDE];
 	uint8_t oldstate = f->state;
 
 	ASSERT(state < FLOW_NUM_STATES);
@@ -150,18 +177,28 @@ static void flow_set_state(struct flow_common *f, enum flow_state state)
 		  FLOW_STATE(f));
 
 	if (MAX(state, oldstate) >= FLOW_STATE_TGT)
-		flow_log_(f, LOG_DEBUG, "%s => %s", pif_name(f->pif[INISIDE]),
-			                            pif_name(f->pif[TGTSIDE]));
+		flow_log_(f, LOG_DEBUG, "%s [%s]:%hu -> [%s]:%hu => %s",
+			  pif_name(f->pif[INISIDE]),
+			  inany_ntop(&ini->eaddr, estr, sizeof(estr)),
+			  ini->eport,
+			  inany_ntop(&ini->faddr, fstr, sizeof(fstr)),
+			  ini->fport,
+			  pif_name(f->pif[TGTSIDE]));
 	else if (MAX(state, oldstate) >= FLOW_STATE_INI)
-		flow_log_(f, LOG_DEBUG, "%s => ?", pif_name(f->pif[INISIDE]));
+		flow_log_(f, LOG_DEBUG, "%s [%s]:%hu -> [%s]:%hu => ?",
+			  pif_name(f->pif[INISIDE]),
+			  inany_ntop(&ini->eaddr, estr, sizeof(estr)),
+			  ini->eport,
+			  inany_ntop(&ini->faddr, fstr, sizeof(fstr)),
+			  ini->fport);
 }
 
 /**
- * flow_initiate() - Move flow to INI, setting INISIDE details
+ * flow_initiate_() - Move flow to INI, setting pif[INISIDE]
  * @flow:	Flow to change state
  * @pif:	pif of the initiating side
  */
-void flow_initiate(union flow *flow, uint8_t pif)
+static void flow_initiate_(union flow *flow, uint8_t pif)
 {
 	struct flow_common *f = &flow->f;
 
@@ -174,6 +211,55 @@ void flow_initiate(union flow *flow, uint8_t pif)
 	flow_set_state(f, FLOW_STATE_INI);
 }
 
+/**
+ * flow_initiate_af() - Move flow to INI, setting INISIDE details
+ * @flow:	Flow to change state
+ * @pif:	pif of the initiating side
+ * @af:		Address family of @eaddr and @faddr
+ * @saddr:	Source address (pointer to in_addr or in6_addr)
+ * @sport:	Endpoint port
+ * @daddr:	Destination address (pointer to in_addr or in6_addr)
+ * @dport:	Destination port
+ *
+ * Return: pointer to the initiating flowside information
+ */
+const struct flowside *flow_initiate_af(union flow *flow, uint8_t pif,
+					sa_family_t af,
+					const void *saddr, in_port_t sport,
+					const void *daddr, in_port_t dport)
+{
+	struct flowside *ini = &flow->f.side[INISIDE];
+
+	flowside_from_af(ini, af, saddr, sport, daddr, dport);
+	flow_initiate_(flow, pif);
+	return ini;
+}
+
+/**
+ * flow_initiate_sa() - Move flow to INI, setting INISIDE details
+ * @flow:	Flow to change state
+ * @pif:	pif of the initiating side
+ * @ssa:	Source socket address
+ * @dport:	Destination port
+ *
+ * Return: pointer to the initiating flowside information
+ */
+const struct flowside *flow_initiate_sa(union flow *flow, uint8_t pif,
+					const union sockaddr_inany *ssa,
+					in_port_t dport)
+{
+	struct flowside *ini = &flow->f.side[INISIDE];
+
+	inany_from_sockaddr(&ini->eaddr, &ini->eport, ssa);
+	if (inany_v4(&ini->eaddr))
+		ini->faddr = inany_any4;
+	else
+		ini->faddr = inany_any6;
+	ini->fport = dport;
+	flow_initiate_(flow, pif);
+	return ini;
+}
+
 /**
  * flow_target() - Move flow to TGT, setting TGTSIDE details
  * @flow:	Flow to change state
diff --git a/flow.h b/flow.h
index b518904..8c6ba60 100644
--- a/flow.h
+++ b/flow.h
@@ -135,11 +135,26 @@ extern const uint8_t flow_proto[];
 #define INISIDE			0	/* Initiating side index */
 #define TGTSIDE			1	/* Target side index */
 
+/**
+ * struct flowside - Address information for one side of a flow
+ * @eaddr:	Endpoint address (remote address from passt's PoV)
+ * @faddr:	Forwarding address (local address from passt's PoV)
+ * @eport:	Endpoint port
+ * @fport:	Forwarding port
+ */
+struct flowside {
+	union inany_addr	faddr;
+	union inany_addr	eaddr;
+	in_port_t		fport;
+	in_port_t		eport;
+};
+
 /**
  * struct flow_common - Common fields for packet flows
  * @state:	State of the flow table entry
  * @type:	Type of packet flow
  * @pif[]:	Interface for each side of the flow
+ * @side[]:	Information for each side of the flow
  */
 struct flow_common {
 #ifdef __GNUC__
@@ -154,6 +169,7 @@ struct flow_common {
 		      "Not enough bits for type field");
 #endif
 	uint8_t		pif[SIDES];
+	struct flowside	side[SIDES];
 };
 
 #define FLOW_INDEX_BITS		17	/* 128k - 1 */
diff --git a/flow_table.h b/flow_table.h
index 4f5d041..586d857 100644
--- a/flow_table.h
+++ b/flow_table.h
@@ -127,7 +127,13 @@ static inline flow_sidx_t flow_sidx(const struct flow_common *f,
 union flow *flow_alloc(void);
 void flow_alloc_cancel(union flow *flow);
 
-void flow_initiate(union flow *flow, uint8_t pif);
+const struct flowside *flow_initiate_af(union flow *flow, uint8_t pif,
+					sa_family_t af,
+					const void *saddr, in_port_t sport,
+					const void *daddr, in_port_t dport);
+const struct flowside *flow_initiate_sa(union flow *flow, uint8_t pif,
+					const union sockaddr_inany *ssa,
+					in_port_t dport);
 void flow_target(union flow *flow, uint8_t pif);
 
 union flow *flow_set_type(union flow *flow, enum flow_type type);
diff --git a/icmp.c b/icmp.c
index 7cf31e6..9b95be2 100644
--- a/icmp.c
+++ b/icmp.c
@@ -162,12 +162,15 @@ static void icmp_ping_close(const struct ctx *c,
  * @id_sock:	Pointer to ping flow entry slot in icmp_id_map[] to update
  * @af:		Address family, AF_INET or AF_INET6
  * @id:		ICMP id for the new socket
+ * @saddr:	Source address
+ * @daddr:	Destination address
  *
  * Return: Newly opened ping flow, or NULL on failure
  */
 static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
 					    struct icmp_ping_flow **id_sock,
-					    sa_family_t af, uint16_t id)
+					    sa_family_t af, uint16_t id,
+					    const void *saddr, const void *daddr)
 {
 	uint8_t flowtype = af == AF_INET ? FLOW_PING4 : FLOW_PING6;
 	union epoll_ref ref = { .type = EPOLL_TYPE_PING };
@@ -179,7 +182,7 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
 	if (!flow)
 		return NULL;
 
-	flow_initiate(flow, PIF_TAP);
+	flow_initiate_af(flow, PIF_TAP, af, saddr, id, daddr, id);
 	flow_target(flow, PIF_HOST);
 	pingf = FLOW_SET_TYPE(flow, flowtype, ping);
 
@@ -285,7 +288,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 	}
 
 	if (!(pingf = *id_sock))
-		if (!(pingf = icmp_ping_new(c, id_sock, af, id)))
+		if (!(pingf = icmp_ping_new(c, id_sock, af, id, saddr, daddr)))
 			return 1;
 
 	pingf->ts = now->tv_sec;
diff --git a/passt.h b/passt.h
index 867e77b..0d76b49 100644
--- a/passt.h
+++ b/passt.h
@@ -17,6 +17,9 @@ union epoll_ref;
 
 #include "pif.h"
 #include "packet.h"
+#include "siphash.h"
+#include "ip.h"
+#include "inany.h"
 #include "flow.h"
 #include "icmp.h"
 #include "fwd.h"
diff --git a/tcp.c b/tcp.c
index c5431f1..286a417 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1666,7 +1666,7 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 	if (!(flow = flow_alloc()))
 		return;
 
-	flow_initiate(flow, PIF_TAP);
+	flow_initiate_af(flow, PIF_TAP, af, saddr, srcport, daddr, dstport);
 
 	flow_target(flow, PIF_HOST);
 	conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
@@ -2351,7 +2351,9 @@ void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 	if (s < 0)
 		goto cancel;
 
-	flow_initiate(flow, ref.tcp_listen.pif);
+	/* FIXME: When listening port has a specific bound address, record that
+	 * as the forwarding address */
+	flow_initiate_sa(flow, ref.tcp_listen.pif, &sa, ref.tcp_listen.port);
 
 	if (sa.sa_family == AF_INET) {
 		const struct in_addr *addr = &sa.sa4.sin_addr;