diff --git a/lte/alt1250/alt1250_netdev.c b/lte/alt1250/alt1250_netdev.c
index ee9e9602a..1f8fff8f2 100644
--- a/lte/alt1250/alt1250_netdev.c
+++ b/lte/alt1250/alt1250_netdev.c
@@ -30,6 +30,8 @@
 
 #include "alt1250_netdev.h"
 
+#define ALT1250_SUBNET_MASK 0xFFFFFF00 /* 255.255.255.0 this is dummy */
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -61,6 +63,8 @@ void alt1250_netdev_ifdown(FAR struct alt1250_s *dev)
   dev->net_dev.d_flags = IFF_DOWN;
 #ifdef CONFIG_NET_IPv4
   memset(&dev->net_dev.d_ipaddr, 0, sizeof(dev->net_dev.d_ipaddr));
+  memset(&dev->net_dev.d_draddr, 0, sizeof(dev->net_dev.d_draddr));
+  memset(&dev->net_dev.d_netmask, 0, sizeof(dev->net_dev.d_netmask));
 #endif
 #ifdef CONFIG_NET_IPv6
   memset(&dev->net_dev.d_ipv6addr, 0, sizeof(dev->net_dev.d_ipv6addr));
@@ -85,6 +89,17 @@ void alt1250_netdev_ifup(FAR struct alt1250_s *dev, FAR lte_pdn_t *pdn)
           inet_pton(AF_INET,
                     (FAR const char *)pdn->address[i].address,
                     (FAR void *)&dev->net_dev.d_ipaddr);
+          inet_pton(AF_INET,
+                    (FAR const char *)pdn->address[i].address,
+                    (FAR void *)&dev->net_dev.d_draddr);
+
+          /* The following parameters are dummy values because
+           * they cannot be obtained from alt1250.
+           */
+
+          dev->net_dev.d_draddr = htonl((ntohl(dev->net_dev.d_draddr) &
+                                         ALT1250_SUBNET_MASK) | 1);
+          dev->net_dev.d_netmask = htonl(ALT1250_SUBNET_MASK);
         }
 #endif
 
diff --git a/lte/alt1250/alt1250_usockif.c b/lte/alt1250/alt1250_usockif.c
index f421361e5..f85d05a61 100644
--- a/lte/alt1250/alt1250_usockif.c
+++ b/lte/alt1250/alt1250_usockif.c
@@ -281,7 +281,7 @@ int usockif_readreqioctl(int fd, FAR struct usrsock_request_buff_s *buf)
         break;
       default:
         dbg_alt1250("Unsupported command:0x%08lx\n", req->cmd);
-        return -EINVAL;
+        return -ENOTTY;
         break;
     }
 
diff --git a/lte/alt1250/usock_handlers/alt1250_ioctl_ifreq.c b/lte/alt1250/usock_handlers/alt1250_ioctl_ifreq.c
index 1bae245f1..666f1cd95 100644
--- a/lte/alt1250/usock_handlers/alt1250_ioctl_ifreq.c
+++ b/lte/alt1250/usock_handlers/alt1250_ioctl_ifreq.c
@@ -391,7 +391,11 @@ int usockreq_ioctl_ifreq(FAR struct alt1250_s *dev,
   *usock_result = OK;
   *usock_xid = request->head.xid;
 
-  if (if_req->ifr_flags & IFF_UP)
+  if (!dev->usock_enable)
+    {
+      *usock_result = -ENOTTY;
+    }
+  else if (if_req->ifr_flags & IFF_UP)
     {
       ret = do_ifup(dev, req, usock_result, usock_xid, ackinfo);
     }
diff --git a/lte/alt1250/usock_handlers/alt1250_sockethdlr.c b/lte/alt1250/usock_handlers/alt1250_sockethdlr.c
index d43e044b9..4eb374390 100644
--- a/lte/alt1250/usock_handlers/alt1250_sockethdlr.c
+++ b/lte/alt1250/usock_handlers/alt1250_sockethdlr.c
@@ -393,11 +393,11 @@ int usockreq_socket(FAR struct alt1250_s *dev,
            request->type != SOCK_CTRL)
     {
       /* If domain is AF_INET while usock_enable is false,
-       * set usockid to -EPROTONOSUPPORT to fallback kernel
+       * set usockid to -ENOTSUP to fallback kernel
        * network stack.
        */
 
-      *usock_result = -EPROTONOSUPPORT;
+      *usock_result = -ENOTSUP;
       return REP_SEND_ACK_WOFREE;
     }