diff --git a/subsys/net/lib/ptp/msg.c b/subsys/net/lib/ptp/msg.c
index c26ee175f1d..a46d30be4aa 100644
--- a/subsys/net/lib/ptp/msg.c
+++ b/subsys/net/lib/ptp/msg.c
@@ -284,13 +284,12 @@ struct ptp_msg *ptp_msg_from_pkt(struct net_pkt *pkt)
 		hdr = net_udp_get_hdr(pkt, NULL);
 	}
 
-	payload = ntohs(hdr->len) - NET_UDPH_LEN;
-
 	if (!hdr) {
 		LOG_ERR("Couldn't retrieve UDP header from the net packet");
 		return NULL;
 	}
 
+	payload = ntohs(hdr->len) - NET_UDPH_LEN;
 	port = ntohs(hdr->dst_port);
 
 	if (port != PTP_SOCKET_PORT_EVENT && port != PTP_SOCKET_PORT_GENERAL) {
diff --git a/subsys/net/lib/ptp/port.c b/subsys/net/lib/ptp/port.c
index f92186628e5..1c6750a918c 100644
--- a/subsys/net/lib/ptp/port.c
+++ b/subsys/net/lib/ptp/port.c
@@ -88,8 +88,9 @@ static int port_msg_send(struct ptp_port *port, struct ptp_msg *msg, enum ptp_so
 
 static void port_timer_set_timeout(struct k_timer *timer, uint8_t factor, int8_t log_seconds)
 {
-	uint64_t timeout = log_seconds < 0 ? (NSEC_PER_SEC * factor) >> (log_seconds * -1) :
-					     (NSEC_PER_SEC * factor) << log_seconds;
+	uint64_t timeout = log_seconds < 0 ?
+		(uint64_t)((NSEC_PER_SEC * factor) >> (log_seconds * -1)) :
+		(uint64_t)((NSEC_PER_SEC * factor) << log_seconds);
 
 	k_timer_start(timer, K_NSEC(timeout), K_NO_WAIT);
 }
@@ -102,14 +103,14 @@ static void port_timer_set_timeout_random(struct k_timer *timer,
 	uint64_t timeout, random_ns;
 
 	if (log_seconds < 0) {
-		timeout = (NSEC_PER_SEC * min_factor) >> -log_seconds;
-		random_ns = NSEC_PER_SEC >> -log_seconds;
+		timeout = (uint64_t)((NSEC_PER_SEC * min_factor) >> -log_seconds);
+		random_ns = (uint64_t)(NSEC_PER_SEC >> -log_seconds);
 	} else {
-		timeout = (NSEC_PER_SEC * min_factor) << log_seconds;
-		random_ns = (span * NSEC_PER_SEC) << log_seconds;
+		timeout = (uint64_t)((NSEC_PER_SEC * min_factor) << log_seconds);
+		random_ns = (uint64_t)((span * NSEC_PER_SEC) << log_seconds);
 	}
 
-	timeout = timeout + (random_ns * (sys_rand32_get() % (1 << 15) + 1) >> 15);
+	timeout = (uint64_t)(timeout + (random_ns * (sys_rand32_get() % (1 << 15) + 1) >> 15));
 	k_timer_start(timer, K_NSEC(timeout), K_NO_WAIT);
 }
 
@@ -970,14 +971,14 @@ static void port_link_monitor(struct net_mgmt_event_callback *cb,
 
 	enum ptp_port_event event = PTP_EVT_NONE;
 	struct ptp_port *port = ptp_clock_port_from_iface(iface);
-	int iface_state = mgmt_event == NET_EVENT_IF_UP ? PORT_LINK_UP : PORT_LINK_DOWN;
+	uint8_t iface_state = mgmt_event == NET_EVENT_IF_UP ? PORT_LINK_UP : PORT_LINK_DOWN;
 
 	if (!port) {
 		return;
 	}
 
 	if (iface_state & port->link_status) {
-		port->link_status = port->link_status;
+		port->link_status = iface_state;
 	} else {
 		port->link_status = iface_state | PORT_LINK_CHANGED;
 		LOG_DBG("Port %d link %s",
@@ -1014,7 +1015,7 @@ void ptp_port_init(struct net_if *iface, void *user_data)
 		return;
 	}
 
-	port = ports + dds->n_ports;
+	port = &ports[dds->n_ports];
 
 	port->iface = iface;
 	port->best = NULL;
@@ -1360,8 +1361,9 @@ int ptp_port_add_foreign_tt(struct ptp_port *port, struct ptp_msg *msg)
 			port->port_ds.id.port_number,
 			port_id_str(&msg->header.src_port_id));
 
-		k_mem_slab_alloc(&foreign_tts_slab, (void **)&foreign, K_NO_WAIT);
-		if (!foreign) {
+		int ret = k_mem_slab_alloc(&foreign_tts_slab, (void **)&foreign, K_NO_WAIT);
+
+		if (ret) {
 			LOG_ERR("Couldn't allocate memory for new foreign timeTransmitter");
 			return 0;
 		}
diff --git a/subsys/net/lib/ptp/tlv.c b/subsys/net/lib/ptp/tlv.c
index 70285915b89..22bec57fd0b 100644
--- a/subsys/net/lib/ptp/tlv.c
+++ b/subsys/net/lib/ptp/tlv.c
@@ -51,7 +51,7 @@ static int tlv_mgmt_post_recv(struct ptp_tlv_mgmt *mgmt_tlv, uint16_t length)
 	enum ptp_mgmt_id id = (enum ptp_mgmt_id)mgmt_tlv->id;
 	struct ptp_tlv_container *container;
 	uint8_t *data;
-	uint16_t data_length;
+	int32_t data_length;
 
 	switch (id) {
 	case PTP_MGMT_NULL_PTP_MANAGEMENT:
diff --git a/subsys/net/lib/ptp/transport.c b/subsys/net/lib/ptp/transport.c
index 64d396e4c69..3543a1faf32 100644
--- a/subsys/net/lib/ptp/transport.c
+++ b/subsys/net/lib/ptp/transport.c
@@ -127,7 +127,7 @@ static int transport_udp_ipv4_open(struct net_if *iface, uint16_t port)
 	}
 
 	tos &= ~0xFC;
-	tos = CONFIG_PTP_DSCP_VALUE << 2;
+	tos |= CONFIG_PTP_DSCP_VALUE << 2;
 	length = sizeof(tos);
 
 	if (zsock_setsockopt(socket, IPPROTO_IP, IP_TOS, &tos, length)) {
@@ -175,7 +175,7 @@ static int transport_udp_ipv6_open(struct net_if *iface, uint16_t port)
 	}
 
 	tclass &= ~0xFC;
-	tclass = CONFIG_PTP_DSCP_VALUE << 2;
+	tclass |= CONFIG_PTP_DSCP_VALUE << 2;
 	length = sizeof(tclass);
 
 	if (zsock_setsockopt(socket, IPPROTO_IPV6, IPV6_TCLASS, &tclass, length)) {
@@ -318,6 +318,8 @@ int ptp_transport_recv(struct ptp_port *port, struct ptp_msg *msg, enum ptp_sock
 
 int ptp_transport_protocol_addr(struct ptp_port *port, uint8_t *addr)
 {
+	__ASSERT_NO_MSG(addr);
+
 	int length = 0;
 
 	if (IS_ENABLED(CONFIG_PTP_UDP_IPv4_PROTOCOL)) {