diff --git a/components/freemodbus/tcp_master/port/port_tcp_master.c b/components/freemodbus/tcp_master/port/port_tcp_master.c
index 0bd76ea..003f709 100644
--- a/components/freemodbus/tcp_master/port/port_tcp_master.c
+++ b/components/freemodbus/tcp_master/port/port_tcp_master.c
@@ -432,11 +432,14 @@ static BOOL xMBTCPPortMasterCheckHost(const CHAR* pcHostStr, ip_addr_t* pxHostAd
         struct in_addr addr4 = ((struct sockaddr_in *) (pxAddrList->ai_addr))->sin_addr;
         inet_addr_to_ip4addr(ip_2_ip4(&xTargetAddr), &addr4);
         pcStr = ip4addr_ntoa_r(ip_2_ip4(&xTargetAddr), cStr, sizeof(cStr));
-    } else {
+    }
+#if CONFIG_LWIP_IPV6
+    else {
         struct in6_addr addr6 = ((struct sockaddr_in6 *) (pxAddrList->ai_addr))->sin6_addr;
         inet6_addr_to_ip6addr(ip_2_ip6(&xTargetAddr), &addr6);
         pcStr = ip6addr_ntoa_r(ip_2_ip6(&xTargetAddr), cStr, sizeof(cStr));
     }
+#endif
     if (pxHostAddr) {
         *pxHostAddr = xTargetAddr;
     }
@@ -496,7 +499,9 @@ static err_t xMBTCPPortMasterConnect(MbSlaveInfo_t* pxInfo)
             struct in_addr addr4 = ((struct sockaddr_in *) (pxCurAddr->ai_addr))->sin_addr;
             inet_addr_to_ip4addr(ip_2_ip4(&xTargetAddr), &addr4);
             pcStr = ip4addr_ntoa_r(ip_2_ip4(&xTargetAddr), cStr, sizeof(cStr));
-        } else if (pxCurAddr->ai_family == AF_INET6) {
+        }
+#if CONFIG_LWIP_IPV6
+        else if (pxCurAddr->ai_family == AF_INET6) {
             struct in6_addr addr6 = ((struct sockaddr_in6 *) (pxCurAddr->ai_addr))->sin6_addr;
             inet6_addr_to_ip6addr(ip_2_ip6(&xTargetAddr), &addr6);
             pcStr = ip6addr_ntoa_r(ip_2_ip6(&xTargetAddr), cStr, sizeof(cStr));
@@ -504,7 +509,7 @@ static err_t xMBTCPPortMasterConnect(MbSlaveInfo_t* pxInfo)
             ((struct sockaddr_in6 *) (pxCurAddr->ai_addr))->sin6_scope_id =
                                 esp_netif_get_netif_impl_index(xMbPortConfig.pvNetIface);
         }
-
+#endif
         if (pxInfo->xSockId <= 0) {
             pxInfo->xSockId = socket(pxCurAddr->ai_family, pxCurAddr->ai_socktype, pxCurAddr->ai_protocol);
             if (pxInfo->xSockId < 0) {
diff --git a/components/freemodbus/tcp_slave/port/port_tcp_slave.c b/components/freemodbus/tcp_slave/port/port_tcp_slave.c
index 01ff9b0..d5d83e7 100644
--- a/components/freemodbus/tcp_slave/port/port_tcp_slave.c
+++ b/components/freemodbus/tcp_slave/port/port_tcp_slave.c
@@ -184,12 +184,11 @@ static int xMBTCPPortAcceptConnection(int xListenSockId, char** pcIPAddr)
     MB_PORT_CHECK((xListenSockId > 0), -1, "Incorrect listen socket ID.");
 
     // Address structure large enough for both IPv4 or IPv6 address
-    struct sockaddr_in6 xSrcAddr;
-
+    struct sockaddr_storage xSrcAddr;
     CHAR cAddrStr[128];
     int xSockId = -1;
     CHAR* pcStr = NULL;
-    socklen_t xSize = sizeof(struct sockaddr_in6);
+    socklen_t xSize = sizeof(struct sockaddr_storage);
 
     // Accept new socket connection if not active
     xSockId = accept(xListenSockId, (struct sockaddr *)&xSrcAddr, &xSize);
@@ -198,11 +197,14 @@ static int xMBTCPPortAcceptConnection(int xListenSockId, char** pcIPAddr)
         close(xSockId);
     } else {
         // Get the sender's ip address as string
-        if (xSrcAddr.sin6_family == PF_INET) {
+        if (xSrcAddr.ss_family == PF_INET) {
             inet_ntoa_r(((struct sockaddr_in *)&xSrcAddr)->sin_addr.s_addr, cAddrStr, sizeof(cAddrStr) - 1);
-        } else if (xSrcAddr.sin6_family == PF_INET6) {
-            inet6_ntoa_r(xSrcAddr.sin6_addr, cAddrStr, sizeof(cAddrStr) - 1);
         }
+#if CONFIG_LWIP_IPV6
+        else if (xSrcAddr.ss_family == PF_INET6) {
+            inet6_ntoa_r(((struct sockaddr_in6 *)&xSrcAddr)->sin6_addr, cAddrStr, sizeof(cAddrStr) - 1);
+        }
+#endif
         ESP_LOGI(MB_TCP_SLAVE_PORT_TAG, "Socket (#%d), accept client connection from address: %s", xSockId, cAddrStr);
         pcStr = calloc(1, strlen(cAddrStr) + 1);
         if (pcStr && pcIPAddr) {