diff --git a/checksum.c b/checksum.c
index c59869c..29769d9 100644
--- a/checksum.c
+++ b/checksum.c
@@ -133,7 +133,8 @@ void csum_ip4_header(struct iphdr *ip4h)
  * @payload:	ICMPv4 packet payload
  * @len:	Length of @payload (not including UDP)
  */
-void csum_udp4(struct udphdr *udp4hr, in_addr_t saddr, in_addr_t daddr,
+void csum_udp4(struct udphdr *udp4hr,
+	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len)
 {
 	/* UDP checksums are optional, so don't bother */
@@ -142,8 +143,8 @@ void csum_udp4(struct udphdr *udp4hr, in_addr_t saddr, in_addr_t daddr,
 	if (UDP4_REAL_CHECKSUMS) {
 		/* UNTESTED: if we did want real UDPv4 checksums, this
 		 * is roughly what we'd need */
-		uint32_t psum = csum_fold(htonl(saddr))
-			+ csum_fold(htonl(daddr))
+		uint32_t psum = csum_fold(saddr.s_addr)
+			+ csum_fold(daddr.s_addr)
 			+ htons(len + sizeof(*udp4hr))
 			+ htons(IPPROTO_UDP);
 		/* Add in partial checksum for the UDP header alone */
diff --git a/checksum.h b/checksum.h
index b87b0d6..c6b6fb4 100644
--- a/checksum.h
+++ b/checksum.h
@@ -14,7 +14,8 @@ uint32_t sum_16b(const void *buf, size_t len);
 uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
 void csum_ip4_header(struct iphdr *ip4h);
-void csum_udp4(struct udphdr *udp4hr, in_addr_t saddr, in_addr_t daddr,
+void csum_udp4(struct udphdr *udp4hr,
+	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len);
 void csum_icmp4(struct icmphdr *ih, const void *payload, size_t len);
 void csum_udp6(struct udphdr *udp6hr,
diff --git a/conf.c b/conf.c
index 3bf7301..f5099a7 100644
--- a/conf.c
+++ b/conf.c
@@ -358,12 +358,12 @@ static void get_dns(struct ctx *c)
 	int dns4_set, dns6_set, dnss_set, dns_set, fd;
 	struct in6_addr *dns6 = &c->ip6.dns[0];
 	struct fqdn *s = c->dns_search;
-	uint32_t *dns4 = &c->ip4.dns[0];
+	struct in_addr *dns4 = &c->ip4.dns[0];
 	struct lineread resolvconf;
 	int line_len;
 	char *line, *p, *end;
 
-	dns4_set = !c->ifi4 || !!*dns4;
+	dns4_set = !c->ifi4 || !IN4_IS_ADDR_UNSPECIFIED(dns4);
 	dns6_set = !c->ifi6 || !IN6_IS_ADDR_UNSPECIFIED(dns6);
 	dnss_set = !!*s->n || c->no_dns_search;
 	dns_set = (dns4_set && dns6_set) || c->no_dns;
@@ -389,15 +389,15 @@ static void get_dns(struct ctx *c)
 			    dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) - 1 &&
 			    inet_pton(AF_INET, p + 1, dns4)) {
 				/* We can only access local addresses via the gw redirect */
-				if (IPV4_IS_LOOPBACK(ntohl(*dns4))) {
+				if (IN4_IS_ADDR_LOOPBACK(dns4)) {
 					if (c->no_map_gw) {
-						*dns4 = 0;
+						dns4->s_addr = htonl(INADDR_ANY);
 						continue;
 					}
 					*dns4 = c->ip4.gw;
 				}
 				dns4++;
-				*dns4 = 0;
+				dns4->s_addr = htonl(INADDR_ANY);
 			}
 
 			if (!dns6_set &&
@@ -566,18 +566,19 @@ static unsigned int conf_ip4(unsigned int ifi,
 		return 0;
 	}
 
-	if (!ip4->gw)
+	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->gw))
 		nl_route(0, ifi, AF_INET, &ip4->gw);
 
-	if (!ip4->addr)
+	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr))
 		nl_addr(0, ifi, AF_INET, &ip4->addr, &ip4->prefix_len, NULL);
 
 	if (!ip4->prefix_len) {
-		if (IN_CLASSA(ntohl(ip4->addr)))
+		in_addr_t addr = ntohl(ip4->addr.s_addr);
+		if (IN_CLASSA(addr))
 			ip4->prefix_len = (32 - IN_CLASSA_NSHIFT);
-		else if (IN_CLASSB(ntohl(ip4->addr)))
+		else if (IN_CLASSB(addr))
 			ip4->prefix_len = (32 - IN_CLASSB_NSHIFT);
-		else if (IN_CLASSC(ntohl(ip4->addr)))
+		else if (IN_CLASSC(addr))
 			ip4->prefix_len = (32 - IN_CLASSC_NSHIFT);
 		else
 			ip4->prefix_len = 32;
@@ -588,7 +589,9 @@ static unsigned int conf_ip4(unsigned int ifi,
 	if (MAC_IS_ZERO(mac))
 		nl_link(0, ifi, mac, 0, 0);
 
-	if (!ip4->gw || !ip4->addr || MAC_IS_ZERO(mac))
+	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->gw) ||
+	    IN4_IS_ADDR_UNSPECIFIED(&ip4->addr) ||
+	    MAC_IS_ZERO(mac))
 		return 0;
 
 	return ifi;
@@ -850,7 +853,7 @@ static void conf_print(const struct ctx *c)
 			     inet_ntop(AF_INET, &c->ip4.gw,   buf4, sizeof(buf4)));
 		}
 
-		for (i = 0; c->ip4.dns[i]; i++) {
+		for (i = 0; !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns[i]); i++) {
 			if (!i)
 				info("DNS:");
 			inet_ntop(AF_INET, &c->ip4.dns[i], buf4, sizeof(buf4));
@@ -1088,7 +1091,7 @@ void conf(struct ctx *c, int argc, char **argv)
 	char *runas = NULL, *logfile = NULL;
 	struct in6_addr *dns6 = c->ip6.dns;
 	struct fqdn *dnss = c->dns_search;
-	uint32_t *dns4 = c->ip4.dns;
+	struct in_addr *dns4 = c->ip4.dns;
 	const char *optstring;
 	unsigned int ifi = 0;
 	int name, ret, b, i;
@@ -1186,11 +1189,11 @@ void conf(struct ctx *c, int argc, char **argv)
 			    !IN6_IS_ADDR_LOOPBACK(&c->ip6.dns_fwd))
 				break;
 
-			if (c->ip4.dns_fwd == htonl(INADDR_ANY)		&&
+			if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_fwd)	&&
 			    inet_pton(AF_INET, optarg, &c->ip4.dns_fwd)	&&
-			    c->ip4.dns_fwd != htonl(INADDR_ANY)		&&
-			    c->ip4.dns_fwd != htonl(INADDR_BROADCAST)	&&
-			    !IPV4_IS_LOOPBACK(ntohl(c->ip4.dns_fwd)))
+			    !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_fwd)	&&
+			    !IN4_IS_ADDR_BROADCAST(&c->ip4.dns_fwd)	&&
+			    !IN4_IS_ADDR_LOOPBACK(&c->ip4.dns_fwd))
 				break;
 
 			err("Invalid DNS forwarding address: %s", optarg);
@@ -1384,12 +1387,12 @@ void conf(struct ctx *c, int argc, char **argv)
 			    !IN6_IS_ADDR_MULTICAST(&c->ip6.addr))
 				break;
 
-			if (c->ip4.addr == htonl(INADDR_ANY)		&&
+			if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addr)	&&
 			    inet_pton(AF_INET, optarg, &c->ip4.addr)	&&
-			    c->ip4.addr != htonl(INADDR_ANY)		&&
-			    c->ip4.addr != htonl(INADDR_BROADCAST)	&&
-			    !IPV4_IS_LOOPBACK(ntohl(c->ip4.addr))	&&
-			    !IN_MULTICAST(ntohl(c->ip4.addr)))
+			    !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addr)	&&
+			    !IN4_IS_ADDR_BROADCAST(&c->ip4.addr)	&&
+			    !IN4_IS_ADDR_LOOPBACK(&c->ip4.addr)		&&
+			    !IN4_IS_ADDR_MULTICAST(&c->ip4.addr))
 				break;
 
 			err("Invalid address: %s", optarg);
@@ -1420,11 +1423,11 @@ void conf(struct ctx *c, int argc, char **argv)
 			    !IN6_IS_ADDR_LOOPBACK(&c->ip6.gw))
 				break;
 
-			if (c->ip4.gw == htonl(INADDR_ANY)		&&
+			if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.gw)		&&
 			    inet_pton(AF_INET, optarg, &c->ip4.gw)	&&
-			    c->ip4.gw != htonl(INADDR_ANY)		&&
-			    c->ip4.gw != htonl(INADDR_BROADCAST)	&&
-			    !IPV4_IS_LOOPBACK(ntohl(c->ip4.gw)))
+			    !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.gw)	&&
+			    !IN4_IS_ADDR_BROADCAST(&c->ip4.gw)		&&
+			    !IN4_IS_ADDR_LOOPBACK(&c->ip4.gw))
 				break;
 
 			err("Invalid gateway address: %s", optarg);
diff --git a/dhcp.c b/dhcp.c
index 076e9b6..0c6f712 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -107,7 +107,7 @@ struct msg {
 	uint16_t secs;
 	uint16_t flags;
 	uint32_t ciaddr;
-	uint32_t yiaddr;
+	struct in_addr yiaddr;
 	uint32_t siaddr;
 	uint32_t giaddr;
 	uint8_t chaddr[16];
@@ -343,7 +343,8 @@ int dhcp(const struct ctx *c, const struct pool *p)
 	/* If the gateway is not on the assigned subnet, send an option 121
 	 * (Classless Static Routing) adding a dummy route to it.
 	 */
-	if ((c->ip4.addr & mask.s_addr) != (c->ip4.gw & mask.s_addr)) {
+	if ((c->ip4.addr.s_addr & mask.s_addr)
+	    != (c->ip4.gw.s_addr & mask.s_addr)) {
 		/* a.b.c.d/32:0.0.0.0, 0:a.b.c.d */
 		opts[121].slen = 14;
 		opts[121].s[0] = 32;
@@ -357,8 +358,10 @@ int dhcp(const struct ctx *c, const struct pool *p)
 		opts[26].s[1] = c->mtu % 256;
 	}
 
-	for (i = 0, opts[6].slen = 0; !c->no_dhcp_dns && c->ip4.dns[i]; i++) {
-		((uint32_t *)opts[6].s)[i] = c->ip4.dns[i];
+	for (i = 0, opts[6].slen = 0;
+	     !c->no_dhcp_dns && !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns[i]);
+	     i++) {
+		((struct in_addr *)opts[6].s)[i] = c->ip4.dns[i];
 		opts[6].slen += sizeof(uint32_t);
 	}
 
diff --git a/icmp.c b/icmp.c
index d388815..b842fa8 100644
--- a/icmp.c
+++ b/icmp.c
@@ -130,8 +130,7 @@ void icmp_sock_handler(const struct ctx *c, union epoll_ref ref,
 		debug("ICMP: echo %s to tap, ID: %i, seq: %i",
 		      (ih->type == ICMP_ECHO) ? "request" : "reply", id, seq);
 
-		tap_icmp4_send(c, sr4->sin_addr.s_addr, tap_ip4_daddr(c),
-			       buf, n);
+		tap_icmp4_send(c, sr4->sin_addr, tap_ip4_daddr(c), buf, n);
 	}
 }
 
diff --git a/passt.c b/passt.c
index 34cd832..fd703de 100644
--- a/passt.c
+++ b/passt.c
@@ -136,7 +136,7 @@ static void timer_init(struct ctx *c, const struct timespec *now)
  * @ip_da:	Pointer to IPv4 destination address, NULL if unchanged
  */
 void proto_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
-			 const uint32_t *ip_da)
+			 const struct in_addr *ip_da)
 {
 	tcp_update_l2_buf(eth_d, eth_s, ip_da);
 	udp_update_l2_buf(eth_d, eth_s, ip_da);
diff --git a/passt.h b/passt.h
index 4cf6078..1a8d74b 100644
--- a/passt.h
+++ b/passt.h
@@ -105,12 +105,12 @@ enum passt_modes {
  * @dns_fwd:		Address forwarded (UDP) to first IPv4 DNS, network order
  */
 struct ip4_ctx {
-	uint32_t addr;
-	uint32_t addr_seen;
+	struct in_addr addr;
+	struct in_addr addr_seen;
 	int prefix_len;
-	uint32_t gw;
-	uint32_t dns[MAXNS + 1];
-	uint32_t dns_fwd;
+	struct in_addr gw;
+	struct in_addr dns[MAXNS + 1];
+	struct in_addr dns_fwd;
 };
 
 /**
@@ -248,6 +248,6 @@ struct ctx {
 };
 
 void proto_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
-			 const uint32_t *ip_da);
+			 const struct in_addr *ip_da);
 
 #endif /* PASST_H */
diff --git a/tap.c b/tap.c
index 0a3ccce..84e93c2 100644
--- a/tap.c
+++ b/tap.c
@@ -92,7 +92,7 @@ int tap_send(const struct ctx *c, const void *data, size_t len)
  *
  * Returns: IPv4 address, network order
  */
-in_addr_t tap_ip4_daddr(const struct ctx *c)
+struct in_addr tap_ip4_daddr(const struct ctx *c)
 {
 	return c->ip4.addr_seen;
 }
@@ -141,7 +141,7 @@ static void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto)
  *
  * Return: pointer at which to write the packet's payload
  */
-static void *tap_push_ip4h(char *buf, in_addr_t src, in_addr_t dst,
+static void *tap_push_ip4h(char *buf, struct in_addr src, struct in_addr dst,
 			   size_t len, uint8_t proto)
 {
 	struct iphdr *ip4h = (struct iphdr *)buf;
@@ -154,8 +154,8 @@ static void *tap_push_ip4h(char *buf, in_addr_t src, in_addr_t dst,
 	ip4h->frag_off = 0;
 	ip4h->ttl = 255;
 	ip4h->protocol = proto;
-	ip4h->saddr = src;
-	ip4h->daddr = dst;
+	ip4h->saddr = src.s_addr;
+	ip4h->daddr = dst.s_addr;
 	csum_ip4_header(ip4h);
 	return ip4h + 1;
 }
@@ -170,8 +170,8 @@ static void *tap_push_ip4h(char *buf, in_addr_t src, in_addr_t dst,
  * @in:		UDP payload contents (not including UDP header)
  * @len:	UDP payload length (not including UDP header)
  */
-void tap_udp4_send(const struct ctx *c, in_addr_t src, in_port_t sport,
-		   in_addr_t dst, in_port_t dport,
+void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
+		   struct in_addr dst, in_port_t dport,
 		   const void *in, size_t len)
 {
 	size_t udplen = len + sizeof(struct udphdr);
@@ -199,7 +199,7 @@ void tap_udp4_send(const struct ctx *c, in_addr_t src, in_port_t sport,
  * @in:		ICMP packet, including ICMP header
  * @len:	ICMP packet length, including ICMP header
  */
-void tap_icmp4_send(const struct ctx *c, in_addr_t src, in_addr_t dst,
+void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst,
 		    void *in, size_t len)
 {
 	char buf[USHRT_MAX];
@@ -448,8 +448,8 @@ resume:
 
 		l4_len = l3_len - hlen;
 
-		if (iph->saddr && c->ip4.addr_seen != iph->saddr) {
-			c->ip4.addr_seen = iph->saddr;
+		if (iph->saddr && c->ip4.addr_seen.s_addr != iph->saddr) {
+			c->ip4.addr_seen.s_addr = iph->saddr;
 			proto_update_l2_buf(NULL, NULL, &c->ip4.addr_seen);
 		}
 
diff --git a/tap.h b/tap.h
index 743bc58..674ab5c 100644
--- a/tap.h
+++ b/tap.h
@@ -6,11 +6,11 @@
 #ifndef TAP_H
 #define TAP_H
 
-in_addr_t tap_ip4_daddr(const struct ctx *c);
-void tap_udp4_send(const struct ctx *c, in_addr_t src, in_port_t sport,
-		   in_addr_t dst, in_port_t dport,
+struct in_addr tap_ip4_daddr(const struct ctx *c);
+void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
+		   struct in_addr dst, in_port_t dport,
 		   const void *in, size_t len);
-void tap_icmp4_send(const struct ctx *c, in_addr_t src, in_addr_t dst,
+void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct in_addr dst,
 		    void *in, size_t len);
 const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
 				     const struct in6_addr *src);
diff --git a/tcp.c b/tcp.c
index e6979a9..7405ba9 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1107,7 +1107,7 @@ static void tcp_update_check_tcp6(struct tcp6_l2_buf_t *buf)
  * @ip_da:	Pointer to IPv4 destination address, NULL if unchanged
  */
 void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
-		       const uint32_t *ip_da)
+		       const struct in_addr *ip_da)
 {
 	int i;
 
@@ -1134,16 +1134,16 @@ void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
 		}
 
 		if (ip_da) {
-			b4f->iph.daddr = b4->iph.daddr = *ip_da;
+			b4f->iph.daddr = b4->iph.daddr = ip_da->s_addr;
 			if (!i) {
 				b4f->iph.saddr = b4->iph.saddr = 0;
 				b4f->iph.tot_len = b4->iph.tot_len = 0;
 				b4f->iph.check = b4->iph.check = 0;
 				b4f->psum = b4->psum = sum_16b(&b4->iph, 20);
 
-				b4->tsum = ((*ip_da >> 16) & 0xffff) +
-					   (*ip_da & 0xffff) +
-					   htons(IPPROTO_TCP);
+				b4->tsum = ((ip_da->s_addr >> 16) & 0xffff) +
+					    (ip_da->s_addr & 0xffff) +
+					    htons(IPPROTO_TCP);
 				b4f->tsum = b4->tsum;
 			} else {
 				b4f->psum = b4->psum = tcp4_l2_buf[0].psum;
@@ -1701,7 +1701,7 @@ do {									\
 		ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
 		b->iph.tot_len = htons(ip_len);
 		b->iph.saddr = conn->a.a4.a.s_addr;
-		b->iph.daddr = c->ip4.addr_seen;
+		b->iph.daddr = c->ip4.addr_seen.s_addr;
 
 		if (check)
 			b->iph.check = *check;
@@ -2048,7 +2048,7 @@ static uint32_t tcp_seq_init(const struct ctx *c, int af, const void *addr,
 		} __attribute__((__packed__)) in = {
 			.src = *(struct in_addr *)addr,
 			.srcport = srcport,
-			.dst = { c->ip4.addr },
+			.dst = c->ip4.addr,
 			.dstport = dstport,
 		};
 
@@ -2176,10 +2176,10 @@ static void tcp_conn_from_tap(struct ctx *c, int af, const void *addr,
 		return;
 
 	if (!c->no_map_gw) {
-		if (af == AF_INET && addr4.sin_addr.s_addr == c->ip4.gw)
-			addr4.sin_addr.s_addr	= htonl(INADDR_LOOPBACK);
+		if (af == AF_INET && IN4_ARE_ADDR_EQUAL(addr, &c->ip4.gw))
+			addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 		if (af == AF_INET6 && IN6_ARE_ADDR_EQUAL(addr, &c->ip6.gw))
-			addr6.sin6_addr		= in6addr_loopback;
+			addr6.sin6_addr	= in6addr_loopback;
 	}
 
 	if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)) {
@@ -2899,30 +2899,28 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref,
 		tcp_hash_insert(c, conn, AF_INET6, &sa6.sin6_addr);
 	} else {
 		struct sockaddr_in sa4;
-		in_addr_t s_addr;
 
 		memcpy(&sa4, &sa, sizeof(sa4));
-		s_addr = ntohl(sa4.sin_addr.s_addr);
 
 		memset(&conn->a.a4.zero,   0, sizeof(conn->a.a4.zero));
 		memset(&conn->a.a4.one, 0xff, sizeof(conn->a.a4.one));
 
-		if (IPV4_IS_LOOPBACK(s_addr) || s_addr == INADDR_ANY ||
-		    htonl(s_addr) == c->ip4.addr_seen)
-			s_addr = ntohl(c->ip4.gw);
+		if (IN4_IS_ADDR_LOOPBACK(&sa4.sin_addr) ||
+		    IN4_IS_ADDR_UNSPECIFIED(&sa4.sin_addr) ||
+		    IN4_ARE_ADDR_EQUAL(&sa4.sin_addr, &c->ip4.addr_seen))
+			sa4.sin_addr = c->ip4.gw;
 
-		s_addr = htonl(s_addr);
-		memcpy(&conn->a.a4.a, &s_addr, sizeof(conn->a.a4.a));
+		conn->a.a4.a = sa4.sin_addr;
 
 		conn->sock_port = ntohs(sa4.sin_port);
 		conn->tap_port = ref.r.p.tcp.tcp.index;
 
-		conn->seq_to_tap = tcp_seq_init(c, AF_INET, &s_addr,
+		conn->seq_to_tap = tcp_seq_init(c, AF_INET, &sa4.sin_addr,
 						conn->sock_port,
 						conn->tap_port,
 						now);
 
-		tcp_hash_insert(c, conn, AF_INET, &s_addr);
+		tcp_hash_insert(c, conn, AF_INET, &sa4.sin_addr);
 	}
 
 	conn->seq_ack_from_tap = conn->seq_to_tap + 1;
@@ -3081,7 +3079,7 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
  * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
  */
-static void tcp_sock_init4(const struct ctx *c, int ns, const in_addr_t *addr,
+static void tcp_sock_init4(const struct ctx *c, int ns, const struct in_addr *addr,
 			   const char *ifname, in_port_t port)
 {
 	union tcp_epoll_ref tref = { .tcp.listen = 1, .tcp.outbound = ns };
@@ -3089,14 +3087,13 @@ static void tcp_sock_init4(const struct ctx *c, int ns, const in_addr_t *addr,
 	int s;
 
 	if (c->mode == MODE_PASTA) {
-		spliced = !addr ||
-			  ntohl(*addr) == INADDR_ANY ||
-			  IPV4_IS_LOOPBACK(ntohl(*addr));
+		spliced = !addr || IN4_IS_ADDR_UNSPECIFIED(addr) ||
+			IN4_IS_ADDR_LOOPBACK(addr);
 
 		if (!addr)
 			addr = &c->ip4.addr;
 
-		tap = !ns && !IPV4_IS_LOOPBACK(ntohl(*addr));
+		tap = !ns && !IN4_IS_ADDR_LOOPBACK(addr);
 	}
 
 	if (ns)
@@ -3117,9 +3114,10 @@ static void tcp_sock_init4(const struct ctx *c, int ns, const in_addr_t *addr,
 	}
 
 	if (spliced) {
+		struct in_addr loopback = { htonl(INADDR_LOOPBACK) };
 		tref.tcp.splice = 1;
 
-		addr = &(uint32_t){ htonl(INADDR_LOOPBACK) };
+		addr = &loopback;
 
 		s = sock_l4(c, AF_INET, IPPROTO_TCP, addr, ifname, port,
 			    tref.u32);
diff --git a/tcp.h b/tcp.h
index 72e7815..3fabb5a 100644
--- a/tcp.h
+++ b/tcp.h
@@ -28,7 +28,7 @@ void tcp_defer_handler(struct ctx *c);
 
 void tcp_sock_set_bufsize(const struct ctx *c, int s);
 void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
-		       const uint32_t *ip_da);
+		       const struct in_addr *ip_da);
 
 /**
  * union tcp_epoll_ref - epoll reference portion for TCP connections
diff --git a/udp.c b/udp.c
index 7ce533d..fca418d 100644
--- a/udp.c
+++ b/udp.c
@@ -298,7 +298,7 @@ static void udp_update_check4(struct udp4_l2_buf_t *buf)
  * @ip_da:	Pointer to IPv4 destination address, NULL if unchanged
  */
 void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
-		       const uint32_t *ip_da)
+		       const struct in_addr *ip_da)
 {
 	int i;
 
@@ -317,7 +317,7 @@ void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
 		}
 
 		if (ip_da) {
-			b4->iph.daddr = *ip_da;
+			b4->iph.daddr = ip_da->s_addr;
 			if (!i) {
 				b4->iph.saddr = 0;
 				b4->iph.tot_len = 0;
@@ -671,30 +671,30 @@ static void udp_sock_fill_data_v4(const struct ctx *c, int n,
 	struct udp4_l2_buf_t *b = &udp4_l2_buf[n];
 	size_t ip_len, buf_len;
 	in_port_t src_port;
-	in_addr_t src;
 
 	ip_len = udp4_l2_mh_sock[n].msg_len + sizeof(b->iph) + sizeof(b->uh);
 
 	b->iph.tot_len = htons(ip_len);
 
-	src = ntohl(b->s_in.sin_addr.s_addr);
 	src_port = ntohs(b->s_in.sin_port);
 
-	if (IPV4_IS_LOOPBACK(src) ||
-	    src == INADDR_ANY || src == ntohl(c->ip4.addr_seen)) {
-		b->iph.saddr = c->ip4.gw;
+	if (IN4_IS_ADDR_LOOPBACK(&b->s_in.sin_addr) ||
+	    IN4_IS_ADDR_UNSPECIFIED(&b->s_in.sin_addr)||
+	    IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.addr_seen)) {
+		b->iph.saddr = c->ip4.gw.s_addr;
 		udp_tap_map[V4][src_port].ts = now->tv_sec;
 		udp_tap_map[V4][src_port].flags |= PORT_LOCAL;
 
-		if (b->s_in.sin_addr.s_addr == c->ip4.addr_seen)
+		if (IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr.s_addr, &c->ip4.addr_seen))
 			udp_tap_map[V4][src_port].flags &= ~PORT_LOOPBACK;
 		else
 			udp_tap_map[V4][src_port].flags |= PORT_LOOPBACK;
 
 		bitmap_set(udp_act[V4][UDP_ACT_TAP], src_port);
-	} else if (c->ip4.dns_fwd &&
-		   src == htonl(c->ip4.dns[0]) && src_port == 53) {
-		b->iph.saddr = c->ip4.dns_fwd;
+	} else if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_fwd) &&
+		   IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.dns[0]) &&
+		   src_port == 53) {
+		b->iph.saddr = c->ip4.dns_fwd.s_addr;
 	} else {
 		b->iph.saddr = b->s_in.sin_addr.s_addr;
 	}
@@ -1016,15 +1016,15 @@ int udp_tap_handler(struct ctx *c, int af, const void *addr,
 
 		udp_tap_map[V4][src].ts = now->tv_sec;
 
-		if (s_in.sin_addr.s_addr == c->ip4.gw && !c->no_map_gw) {
+		if (IN4_ARE_ADDR_EQUAL(&s_in.sin_addr, &c->ip4.gw) && !c->no_map_gw) {
 			if (!(udp_tap_map[V4][dst].flags & PORT_LOCAL) ||
 			    (udp_tap_map[V4][dst].flags & PORT_LOOPBACK))
 				s_in.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 			else
-				s_in.sin_addr.s_addr = c->ip4.addr_seen;
-		} else if (s_in.sin_addr.s_addr == c->ip4.dns_fwd &&
+				s_in.sin_addr = c->ip4.addr_seen;
+		} else if (IN4_ARE_ADDR_EQUAL(&s_in.sin_addr, &c->ip4.dns_fwd) &&
 			   ntohs(s_in.sin_port) == 53) {
-			s_in.sin_addr.s_addr = c->ip4.dns[0];
+			s_in.sin_addr = c->ip4.dns[0];
 		}
 	} else {
 		s_in6 = (struct sockaddr_in6) {
diff --git a/udp.h b/udp.h
index b4ee8b7..2ac8610 100644
--- a/udp.h
+++ b/udp.h
@@ -17,7 +17,7 @@ void udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 int udp_init(struct ctx *c);
 void udp_timer(struct ctx *c, const struct timespec *ts);
 void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
-		       const uint32_t *ip_da);
+		       const struct in_addr *ip_da);
 
 /**
  * union udp_epoll_ref - epoll reference portion for TCP connections
diff --git a/util.h b/util.h
index c498a80..2d4e1ff 100644
--- a/util.h
+++ b/util.h
@@ -69,8 +69,16 @@
 #define MAC_ZERO		((uint8_t [ETH_ALEN]){ 0 })
 #define MAC_IS_ZERO(addr)	(!memcmp((addr), MAC_ZERO, ETH_ALEN))
 
-#define IPV4_IS_LOOPBACK(addr)						\
-	((addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
+#define IN4_IS_ADDR_UNSPECIFIED(a) \
+	((a)->s_addr == htonl(INADDR_ANY))
+#define IN4_IS_ADDR_BROADCAST(a) \
+	((a)->s_addr == htonl(INADDR_BROADCAST))
+#define IN4_IS_ADDR_LOOPBACK(a) \
+	(ntohl((a)->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
+#define IN4_IS_ADDR_MULTICAST(a) \
+	(IN_MULTICAST(ntohl((a)->s_addr)))
+#define IN4_ARE_ADDR_EQUAL(a, b) \
+	(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
 
 #define NS_FN_STACK_SIZE	(RLIMIT_STACK_VAL * 1024 / 8)
 #define NS_CALL(fn, arg)						\