diff --git a/icmp.c b/icmp.c
index 0eb5bfe..8abc94b 100644
--- a/icmp.c
+++ b/icmp.c
@@ -160,6 +160,9 @@ int icmp_tap_handler(const struct ctx *c, int af, const void *addr,
 		if (!ih)
 			return 1;
 
+		if (ih->type != ICMP_ECHO && ih->type != ICMP_ECHOREPLY)
+			return 1;
+
 		sa.sin_port = ih->un.echo.id;
 
 		iref.icmp.id = id = ntohs(ih->un.echo.id);
@@ -179,8 +182,9 @@ int icmp_tap_handler(const struct ctx *c, int af, const void *addr,
 		bitmap_set(icmp_act[V4], id);
 
 		sa.sin_addr = *(struct in_addr *)addr;
-		sendto(s, ih, sizeof(*ih) + plen, MSG_NOSIGNAL,
-		       (struct sockaddr *)&sa, sizeof(sa));
+		if (sendto(s, ih, sizeof(*ih) + plen, MSG_NOSIGNAL,
+			   (struct sockaddr *)&sa, sizeof(sa)) < 0)
+			debug("ICMP: failed to relay request to socket");
 	} else if (af == AF_INET6) {
 		union icmp_epoll_ref iref = { .icmp.v6 = 1 };
 		struct sockaddr_in6 sa = {
@@ -216,8 +220,9 @@ int icmp_tap_handler(const struct ctx *c, int af, const void *addr,
 		bitmap_set(icmp_act[V6], id);
 
 		sa.sin6_addr = *(struct in6_addr *)addr;
-		sendto(s, ih, sizeof(*ih) + plen, MSG_NOSIGNAL,
-		       (struct sockaddr *)&sa, sizeof(sa));
+		if (sendto(s, ih, sizeof(*ih) + plen, MSG_NOSIGNAL,
+			   (struct sockaddr *)&sa, sizeof(sa)) < 1)
+			debug("ICMPv6: failed to relay request to socket");
 	}
 
 	return 1;
diff --git a/netlink.c b/netlink.c
index 5902dc4..78c1186 100644
--- a/netlink.c
+++ b/netlink.c
@@ -60,7 +60,8 @@ ns:
 		return 0;
 
 #ifdef NETLINK_GET_STRICT_CHK
-	setsockopt(*s, SOL_NETLINK, NETLINK_GET_STRICT_CHK, &y, sizeof(y));
+	if (setsockopt(*s, SOL_NETLINK, NETLINK_GET_STRICT_CHK, &y, sizeof(y)))
+		debug("netlink: cannot set NETLINK_GET_STRICT_CHK on %i", *s);
 #endif
 
 	ns_enter((struct ctx *)arg);
@@ -152,7 +153,8 @@ unsigned int nl_get_ext_if(int *v4, int *v6)
 	char buf[BUFSIZ];
 	long *word, tmp;
 	uint8_t *vmap;
-	size_t n, na;
+	ssize_t n;
+	size_t na;
 	int *v;
 
 	if (*v4 == IP_VERSION_PROBE) {
@@ -168,7 +170,9 @@ v6:
 		return 0;
 	}
 
-	n = nl_req(0, buf, &req, sizeof(req));
+	if ((n = nl_req(0, buf, &req, sizeof(req))) < 0)
+		return 0;
+
 	nh = (struct nlmsghdr *)buf;
 
 	for ( ; NLMSG_OK(nh, n); nh = NLMSG_NEXT(nh, n)) {
@@ -289,7 +293,8 @@ void nl_route(int ns, unsigned int ifi, sa_family_t af, void *gw)
 	struct rtattr *rta;
 	struct rtmsg *rtm;
 	char buf[BUFSIZ];
-	size_t n, na;
+	ssize_t n;
+	size_t na;
 
 	if (set) {
 		if (af == AF_INET6) {
@@ -323,8 +328,7 @@ void nl_route(int ns, unsigned int ifi, sa_family_t af, void *gw)
 		req.nlh.nlmsg_flags |= NLM_F_DUMP;
 	}
 
-	n = nl_req(ns, buf, &req, req.nlh.nlmsg_len);
-	if (set)
+	if (set || (n = nl_req(ns, buf, &req, req.nlh.nlmsg_len)) < 0)
 		return;
 
 	nh = (struct nlmsghdr *)buf;
@@ -398,7 +402,8 @@ void nl_addr(int ns, unsigned int ifi, sa_family_t af,
 	struct nlmsghdr *nh;
 	struct rtattr *rta;
 	char buf[BUFSIZ];
-	size_t n, na;
+	ssize_t n;
+	size_t na;
 
 	if (set) {
 		if (af == AF_INET6) {
@@ -430,8 +435,7 @@ void nl_addr(int ns, unsigned int ifi, sa_family_t af,
 		req.nlh.nlmsg_flags |= NLM_F_DUMP;
 	}
 
-	n = nl_req(ns, buf, &req, req.nlh.nlmsg_len);
-	if (set)
+	if (set || (n = nl_req(ns, buf, &req, req.nlh.nlmsg_len)) < 0)
 		return;
 
 	nh = (struct nlmsghdr *)buf;
@@ -504,14 +508,17 @@ void nl_link(int ns, unsigned int ifi, void *mac, int up, int mtu)
 	struct nlmsghdr *nh;
 	struct rtattr *rta;
 	char buf[BUFSIZ];
-	size_t n, na;
+	ssize_t n;
+	size_t na;
 
 	if (!MAC_IS_ZERO(mac)) {
 		req.nlh.nlmsg_len = sizeof(req);
 		memcpy(req.set.mac, mac, ETH_ALEN);
 		req.rta.rta_type = IFLA_ADDRESS;
 		req.rta.rta_len = RTA_LENGTH(ETH_ALEN);
-		nl_req(ns, buf, &req, req.nlh.nlmsg_len);
+		if (nl_req(ns, buf, &req, req.nlh.nlmsg_len) < 0)
+			return;
+
 		up = 0;
 	}
 
@@ -520,17 +527,20 @@ void nl_link(int ns, unsigned int ifi, void *mac, int up, int mtu)
 		req.set.mtu.mtu = mtu;
 		req.rta.rta_type = IFLA_MTU;
 		req.rta.rta_len = RTA_LENGTH(sizeof(unsigned int));
-		nl_req(ns, buf, &req, req.nlh.nlmsg_len);
+		if (nl_req(ns, buf, &req, req.nlh.nlmsg_len) < 0)
+			return;
+
 		up = 0;
 	}
 
-	if (up)
-		nl_req(ns, buf, &req, req.nlh.nlmsg_len);
+	if (up && nl_req(ns, buf, &req, req.nlh.nlmsg_len) < 0)
+		return;
 
 	if (change)
 		return;
 
-	n = nl_req(ns, buf, &req, req.nlh.nlmsg_len);
+	if ((n = nl_req(ns, buf, &req, req.nlh.nlmsg_len)) < 0)
+		return;
 
 	nh = (struct nlmsghdr *)buf;
 	for ( ; NLMSG_OK(nh, n); nh = NLMSG_NEXT(nh, n)) {
diff --git a/qrap.c b/qrap.c
index 3ee73a7..50eea89 100644
--- a/qrap.c
+++ b/qrap.c
@@ -234,8 +234,10 @@ int main(int argc, char **argv)
 valid_args:
 	for (i = 1; i < UNIX_SOCK_MAX; i++) {
 		s = socket(AF_UNIX, SOCK_STREAM, 0);
-		setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
-		setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+		if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
+			perror("setsockopt SO_RCVTIMEO");
+		if (setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)))
+			perror("setsockopt SO_SNDTIMEO");
 
 		if (s < 0) {
 			perror("socket");
@@ -263,8 +265,11 @@ valid_args:
 	}
 
 	tv.tv_usec = 0;
-	setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
-	setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+	if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
+		perror("setsockopt, SO_RCVTIMEO reset");
+	if (setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)))
+		perror("setsockopt, SO_SNDTIMEO reset");
+
 	fprintf(stderr, "Connected to %s\n", addr.sun_path);
 
 	if (dup2(s, (int)fd) < 0) {
diff --git a/tap.c b/tap.c
index f8222a2..e4dd804 100644
--- a/tap.c
+++ b/tap.c
@@ -84,7 +84,8 @@ int tap_send(const struct ctx *c, const void *data, size_t len, int vnet_pre)
 		} else {
 			uint32_t vnet_len = htonl(len);
 
-			send(c->fd_tap, &vnet_len, 4, flags);
+			if (send(c->fd_tap, &vnet_len, 4, flags) < 0)
+				return -1;
 		}
 
 		return send(c->fd_tap, data, len, flags);
@@ -150,7 +151,8 @@ void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto,
 			ih->checksum = csum_unaligned(ih, len, 0);
 		}
 
-		tap_send(c, buf, len + sizeof(*iph) + sizeof(*eh), 1);
+		if (tap_send(c, buf, len + sizeof(*iph) + sizeof(*eh), 1) < 0)
+			debug("tap: failed to send %lu bytes (IPv4)", len);
 	} else {
 		struct ipv6hdr *ip6h = (struct ipv6hdr *)(eh + 1);
 		char *data = (char *)(ip6h + 1);
@@ -201,7 +203,8 @@ void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto,
 			ip6h->flow_lbl[2] = (flow >> 0) & 0xff;
 		}
 
-		tap_send(c, buf, len + sizeof(*ip6h) + sizeof(*eh), 1);
+		if (tap_send(c, buf, len + sizeof(*ip6h) + sizeof(*eh), 1) < 1)
+			debug("tap: failed to send %lu bytes (IPv6)", len);
 	}
 }
 
@@ -862,11 +865,13 @@ static void tap_sock_unix_new(struct ctx *c)
 
 	c->fd_tap = accept4(c->fd_tap_listen, NULL, NULL, 0);
 
-	if (!c->low_rmem)
-		setsockopt(c->fd_tap, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v));
+	if (!c->low_rmem &&
+	    setsockopt(c->fd_tap, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v)))
+		trace("tap: failed to set SO_RCVBUF to %i", v);
 
-	if (!c->low_wmem)
-		setsockopt(c->fd_tap, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v));
+	if (!c->low_wmem &&
+	    setsockopt(c->fd_tap, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v)))
+		trace("tap: failed to set SO_SNDBUF to %i", v);
 
 	ev.data.fd = c->fd_tap;
 	ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
diff --git a/tcp.c b/tcp.c
index 858eb41..92cefab 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1053,11 +1053,11 @@ void tcp_sock_set_bufsize(const struct ctx *c, int s)
 	if (s == -1)
 		return;
 
-	if (!c->low_rmem)
-		setsockopt(s, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v));
+	if (!c->low_rmem && setsockopt(s, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v)))
+		trace("TCP: failed to set SO_RCVBUF to %i", v);
 
-	if (!c->low_wmem)
-		setsockopt(s, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v));
+	if (!c->low_wmem && setsockopt(s, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v)))
+		trace("TCP: failed to set SO_SNDBUF to %i", v);
 }
 
 /**
@@ -1547,7 +1547,8 @@ static void tcp_l2_buf_flush_part(const struct ctx *c,
 
 	missing = end - sent;
 	p = (char *)iov->iov_base + iov->iov_len - missing;
-	send(c->fd_tap, p, missing, MSG_NOSIGNAL);
+	if (send(c->fd_tap, p, missing, MSG_NOSIGNAL))
+		debug("TCP: failed to flush %lu missing bytes to tap", missing);
 }
 
 /**
@@ -2010,6 +2011,7 @@ static void tcp_clamp_window(const struct ctx *c, struct tcp_conn *conn,
 			     unsigned wnd)
 {
 	uint32_t prev_scaled = conn->wnd_from_tap << conn->ws_from_tap;
+	int s = conn->sock;
 
 	wnd <<= conn->ws_from_tap;
 	wnd = MIN(MAX_WINDOW, wnd);
@@ -2025,7 +2027,9 @@ static void tcp_clamp_window(const struct ctx *c, struct tcp_conn *conn,
 	}
 
 	conn->wnd_from_tap = MIN(wnd >> conn->ws_from_tap, USHRT_MAX);
-	setsockopt(conn->sock, SOL_TCP, TCP_WINDOW_CLAMP, &wnd, sizeof(wnd));
+	if (setsockopt(s, SOL_TCP, TCP_WINDOW_CLAMP, &wnd, sizeof(wnd)))
+		trace("TCP: failed to set TCP_WINDOW_CLAMP on socket %i", s);
+
 	conn_flag(c, conn, WND_CLAMPED);
 }
 
@@ -2209,7 +2213,8 @@ static void tcp_conn_from_tap(struct ctx *c, int af, const void *addr,
 	conn->wnd_to_tap = WINDOW_DEFAULT;
 
 	mss = tcp_conn_tap_mss(c, conn, opts, optlen);
-	setsockopt(s, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss));
+	if (setsockopt(s, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss)))
+		trace("TCP: failed to set TCP_MAXSEG on socket %i", s);
 	MSS_SET(conn, mss);
 
 	tcp_get_tap_ws(conn, opts, optlen);
diff --git a/tcp_splice.c b/tcp_splice.c
index 24a3b4b..84df8ed 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -376,8 +376,15 @@ static int tcp_splice_connect_finish(const struct ctx *c,
 			return -EIO;
 		}
 
-		fcntl(conn->pipe_a_b[0], F_SETPIPE_SZ, c->tcp.pipe_size);
-		fcntl(conn->pipe_b_a[0], F_SETPIPE_SZ, c->tcp.pipe_size);
+		if (fcntl(conn->pipe_a_b[0], F_SETPIPE_SZ, c->tcp.pipe_size)) {
+			trace("TCP (spliced): cannot set a->b pipe size to %lu",
+			      c->tcp.pipe_size);
+		}
+
+		if (fcntl(conn->pipe_b_a[0], F_SETPIPE_SZ, c->tcp.pipe_size)) {
+			trace("TCP (spliced): cannot set b->a pipe size to %lu",
+			      c->tcp.pipe_size);
+		}
 	}
 
 	if (!(conn->events & ESTABLISHED))
@@ -428,7 +435,11 @@ static int tcp_splice_connect(const struct ctx *c, struct tcp_splice_conn *conn,
 	if (s < 0)
 		tcp_sock_set_bufsize(c, conn->b);
 
-	setsockopt(conn->b, SOL_TCP, TCP_QUICKACK, &((int){ 1 }), sizeof(int));
+	if (setsockopt(conn->b, SOL_TCP, TCP_QUICKACK,
+		       &((int){ 1 }), sizeof(int))) {
+		trace("TCP (spliced): failed to set TCP_QUICKACK on socket %i",
+		      conn->b);
+	}
 
 	if (CONN_V6(conn)) {
 		sa = (struct sockaddr *)&addr6;
@@ -565,8 +576,11 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 		if ((s = accept4(ref.r.s, NULL, NULL, SOCK_NONBLOCK)) < 0)
 			return;
 
-		setsockopt(s, SOL_TCP, TCP_QUICKACK, &((int){ 1 }),
-			   sizeof(int));
+		if (setsockopt(s, SOL_TCP, TCP_QUICKACK, &((int){ 1 }),
+			       sizeof(int))) {
+			trace("TCP (spliced): failed to set TCP_QUICKACK on %i",
+			      s);
+		}
 
 		conn = CONN(c->tcp.splice_conn_count++);
 		conn->a = s;
@@ -817,10 +831,17 @@ static void tcp_splice_pipe_refill(const struct ctx *c)
 			continue;
 		}
 
-		fcntl(splice_pipe_pool[i][0][0], F_SETPIPE_SZ,
-		      c->tcp.pipe_size);
-		fcntl(splice_pipe_pool[i][1][0], F_SETPIPE_SZ,
-		      c->tcp.pipe_size);
+		if (fcntl(splice_pipe_pool[i][0][0], F_SETPIPE_SZ,
+			  c->tcp.pipe_size)) {
+			trace("TCP (spliced): cannot set a->b pipe size to %lu",
+			      c->tcp.pipe_size);
+		}
+
+		if (fcntl(splice_pipe_pool[i][1][0], F_SETPIPE_SZ,
+			  c->tcp.pipe_size)) {
+			trace("TCP (spliced): cannot set b->a pipe size to %lu",
+			      c->tcp.pipe_size);
+		}
 	}
 }
 
@@ -850,15 +871,21 @@ void tcp_splice_timer(struct ctx *c)
 
 		if ( (conn->flags & RCVLOWAT_SET_A) &&
 		    !(conn->flags & RCVLOWAT_ACT_A)) {
-			setsockopt(conn->a, SOL_SOCKET, SO_RCVLOWAT,
-				   &((int){ 1 }), sizeof(int));
+			if (setsockopt(conn->a, SOL_SOCKET, SO_RCVLOWAT,
+				       &((int){ 1 }), sizeof(int))) {
+				trace("TCP (spliced): can't set SO_RCVLOWAT on "
+				      "%i", conn->a);
+			}
 			conn_flag(c, conn, ~RCVLOWAT_SET_A);
 		}
 
 		if ( (conn->flags & RCVLOWAT_SET_B) &&
 		    !(conn->flags & RCVLOWAT_ACT_B)) {
-			setsockopt(conn->b, SOL_SOCKET, SO_RCVLOWAT,
-				   &((int){ 1 }), sizeof(int));
+			if (setsockopt(conn->b, SOL_SOCKET, SO_RCVLOWAT,
+				       &((int){ 1 }), sizeof(int))) {
+				trace("TCP (spliced): can't set SO_RCVLOWAT on "
+				      "%i", conn->b);
+			}
 			conn_flag(c, conn, ~RCVLOWAT_SET_B);
 		}
 
diff --git a/udp.c b/udp.c
index 1c0fdc6..cbd3ac8 100644
--- a/udp.c
+++ b/udp.c
@@ -938,7 +938,8 @@ void udp_sock_handler(const struct ctx *c, union epoll_ref ref, uint32_t events,
 
 			last_mh->msg_iov = &last_mh->msg_iov[i];
 
-			sendmsg(c->fd_tap, last_mh, MSG_NOSIGNAL);
+			if (sendmsg(c->fd_tap, last_mh, MSG_NOSIGNAL) < 0)
+				debug("UDP: %li bytes to tap missing", missing);
 
 			*iov_base -= first_offset;
 			break;
diff --git a/util.c b/util.c
index 81cf744..c3475d6 100644
--- a/util.c
+++ b/util.c
@@ -154,7 +154,8 @@ void passt_vsyslog(int pri, const char *format, va_list ap)
 	if (log_opt & LOG_PERROR)
 		fprintf(stderr, "%s", buf + sizeof("<0>"));
 
-	send(log_sock, buf, n, 0);
+	if (send(log_sock, buf, n, 0) != n)
+		fprintf(stderr, "Failed to send %i bytes to syslog\n", n);
 }
 
 #define IPV6_NH_OPT(nh)							\
@@ -239,7 +240,7 @@ int sock_l4(const struct ctx *c, int af, uint8_t proto, uint16_t port,
 	};
 	const struct sockaddr *sa;
 	struct epoll_event ev;
-	int fd, sl, one = 1;
+	int fd, sl, y = 1;
 
 	if (proto != IPPROTO_TCP && proto != IPPROTO_UDP &&
 	    proto != IPPROTO_ICMP && proto != IPPROTO_ICMPV6)
@@ -287,10 +288,12 @@ int sock_l4(const struct ctx *c, int af, uint8_t proto, uint16_t port,
 		sa = (const struct sockaddr *)&addr6;
 		sl = sizeof(addr6);
 
-		setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+		if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &y, sizeof(y)))
+			debug("Failed to set IPV6_V6ONLY on socket %i", fd);
 	}
 
-	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &y, sizeof(y)))
+		debug("Failed to set IPV6_V6ONLY on socket %i", fd);
 
 	if (bind(fd, sa, sl) < 0) {
 		/* We'll fail to bind to low ports if we don't have enough