diff --git a/conf.c b/conf.c
index 7286f92..0631b00 100644
--- a/conf.c
+++ b/conf.c
@@ -648,12 +648,24 @@ static unsigned int conf_ip4(unsigned int ifi,
 		return 0;
 	}
 
-	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->gw))
-		nl_route_get_def(nl_sock, ifi, AF_INET, &ip4->gw);
+	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->gw)) {
+		int rc = nl_route_get_def(nl_sock, ifi, AF_INET, &ip4->gw);
+		if (rc < 0) {
+			err("Couldn't discover IPv4 gateway address: %s",
+			    strerror(-rc));
+			return 0;
+		}
+	}
 
-	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr))
-		nl_addr_get(nl_sock, ifi, AF_INET,
-			    &ip4->addr, &ip4->prefix_len, NULL);
+	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr)) {
+		int rc = nl_addr_get(nl_sock, ifi, AF_INET,
+				     &ip4->addr, &ip4->prefix_len, NULL);
+		if (rc < 0) {
+			err("Couldn't discover IPv4 address: %s",
+			    strerror(-rc));
+			return 0;
+		}
+	}
 
 	if (!ip4->prefix_len) {
 		in_addr_t addr = ntohl(ip4->addr.s_addr);
@@ -669,8 +681,15 @@ static unsigned int conf_ip4(unsigned int ifi,
 
 	memcpy(&ip4->addr_seen, &ip4->addr, sizeof(ip4->addr_seen));
 
-	if (MAC_IS_ZERO(mac))
-		nl_link_get_mac(nl_sock, ifi, mac);
+	if (MAC_IS_ZERO(mac)) {
+		int rc = nl_link_get_mac(nl_sock, ifi, mac);
+		if (rc < 0) {
+			char ifname[IFNAMSIZ];
+			err("Couldn't discover MAC for %s: %s",
+			    if_indextoname(ifi, ifname), strerror(-rc));
+			return 0;
+		}
+	}
 
 	if (IN4_IS_ADDR_UNSPECIFIED(&ip4->addr) ||
 	    MAC_IS_ZERO(mac))
@@ -691,6 +710,7 @@ static unsigned int conf_ip6(unsigned int ifi,
 			     struct ip6_ctx *ip6, unsigned char *mac)
 {
 	int prefix_len = 0;
+	int rc;
 
 	if (!ifi)
 		ifi = nl_get_ext_if(nl_sock, AF_INET6);
@@ -700,18 +720,35 @@ static unsigned int conf_ip6(unsigned int ifi,
 		return 0;
 	}
 
-	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->gw))
-		nl_route_get_def(nl_sock, ifi, AF_INET6, &ip6->gw);
+	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->gw)) {
+		rc = nl_route_get_def(nl_sock, ifi, AF_INET6, &ip6->gw);
+		if (rc < 0) {
+			err("Couldn't discover IPv6 gateway address: %s",
+			    strerror(-rc));
+			return 0;
+		}
+	}
 
-	nl_addr_get(nl_sock, ifi, AF_INET6,
-		    IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ? &ip6->addr : NULL,
-		    &prefix_len, &ip6->addr_ll);
+	rc = nl_addr_get(nl_sock, ifi, AF_INET6,
+			 IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ? &ip6->addr : NULL,
+			 &prefix_len, &ip6->addr_ll);
+	if (rc < 0) {
+		err("Couldn't discover IPv6 address: %s", strerror(-rc));
+		return 0;
+	}
 
 	memcpy(&ip6->addr_seen, &ip6->addr, sizeof(ip6->addr));
 	memcpy(&ip6->addr_ll_seen, &ip6->addr_ll, sizeof(ip6->addr_ll));
 
-	if (MAC_IS_ZERO(mac))
-		nl_link_get_mac(0, ifi, mac);
+	if (MAC_IS_ZERO(mac)) {
+		rc = nl_link_get_mac(nl_sock, ifi, mac);
+		if (rc < 0) {
+			char ifname[IFNAMSIZ];
+			err("Couldn't discover MAC for %s: %s",
+			    if_indextoname(ifi, ifname), strerror(-rc));
+			return 0;
+		}
+	}
 
 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ||
 	    IN6_IS_ADDR_UNSPECIFIED(&ip6->addr_ll) ||
diff --git a/netlink.c b/netlink.c
index a60bd05..051d46c 100644
--- a/netlink.c
+++ b/netlink.c
@@ -277,6 +277,8 @@ unsigned int nl_get_ext_if(int s, sa_family_t af)
 			ifi = *(unsigned int *)RTA_DATA(rta);
 		}
 	}
+	if (status < 0)
+		warn("netlink: RTM_GETROUTE failed: %s", strerror(-status));
 
 	return ifi;
 }
@@ -287,8 +289,10 @@ unsigned int nl_get_ext_if(int s, sa_family_t af)
  * @ifi:	Interface index
  * @af:		Address family
  * @gw:		Default gateway to fill on NL_GET
+ *
+ * Return: 0 on success, negative error code on failure
  */
-void nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw)
+int nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -329,6 +333,7 @@ void nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw)
 			found = true;
 		}
 	}
+	return status;
 }
 
 /**
@@ -507,9 +512,11 @@ void nl_route_dup(int s_src, unsigned int ifi_src,
  * @addr:	Global address to fill
  * @prefix_len:	Mask or prefix length, to fill (for IPv4)
  * @addr_l:	Link-scoped address to fill (for IPv6)
+ *
+ * Return: 9 on success, negative error code on failure
  */
-void nl_addr_get(int s, unsigned int ifi, sa_family_t af,
-		 void *addr, int *prefix_len, void *addr_l)
+int nl_addr_get(int s, unsigned int ifi, sa_family_t af,
+		void *addr, int *prefix_len, void *addr_l)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -550,6 +557,7 @@ void nl_addr_get(int s, unsigned int ifi, sa_family_t af,
 				memcpy(addr_l, RTA_DATA(rta), RTA_PAYLOAD(rta));
 		}
 	}
+	return status;
 }
 
 /**
@@ -677,8 +685,10 @@ void nl_addr_dup(int s_src, unsigned int ifi_src,
  * @s:		Netlink socket
  * @ifi:	Interface index
  * @mac:	Fill with current MAC address
+ *
+ * Return: 0 on success, negative error code on failure
  */
-void nl_link_get_mac(int s, unsigned int ifi, void *mac)
+int nl_link_get_mac(int s, unsigned int ifi, void *mac)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -707,6 +717,7 @@ void nl_link_get_mac(int s, unsigned int ifi, void *mac)
 			memcpy(mac, RTA_DATA(rta), ETH_ALEN);
 		}
 	}
+	return status;
 }
 
 /**
diff --git a/netlink.h b/netlink.h
index 977244b..b831405 100644
--- a/netlink.h
+++ b/netlink.h
@@ -11,17 +11,17 @@ extern int nl_sock_ns;
 
 void nl_sock_init(const struct ctx *c, bool ns);
 unsigned int nl_get_ext_if(int s, sa_family_t af);
-void nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw);
+int nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw);
 int nl_route_set_def(int s, unsigned int ifi, sa_family_t af, void *gw);
 void nl_route_dup(int s_src, unsigned int ifi_src,
 		  int s_dst, unsigned int ifi_dst, sa_family_t af);
-void nl_addr_get(int s, unsigned int ifi, sa_family_t af,
-		 void *addr, int *prefix_len, void *addr_l);
+int nl_addr_get(int s, unsigned int ifi, sa_family_t af,
+		void *addr, int *prefix_len, void *addr_l);
 int nl_addr_set(int s, unsigned int ifi, sa_family_t af,
 		void *addr, int prefix_len);
 void nl_addr_dup(int s_src, unsigned int ifi_src,
 		 int s_dst, unsigned int ifi_dst, sa_family_t af);
-void nl_link_get_mac(int s, unsigned int ifi, void *mac);
+int nl_link_get_mac(int s, unsigned int ifi, void *mac);
 int nl_link_set_mac(int s, unsigned int ifi, void *mac);
 int nl_link_up(int s, unsigned int ifi, int mtu);