CC3220: Internal DNS server in AP mode

Hi Salvatore,

This is a known issue that the SL_NETAPP_DNS_SERVER_ID config is not persistent. As a workaround, we suggest calling sl_NetAppStop with another app like mDNS or something you are not using. For example:

sl_NetAppStop(SL_NETAPP_MDNS_ID | SL_NETAPP_DNS_SERVER_ID);

Best regards,

Sarah

Hi Salvatore,

Stopping the DNS server worked for me. Keep in mind that sl_NetAppStop only works for the mode the network processor is currently in (station or AP).

I tested this with the out_of_box application. With the out_of_box as-is and the DNS running by default, before provisioning, I connected to the CC3220 as an AP and successfully navigated to mysimplelink.net. I tried the same steps with the DNS stopped as described and mysimplelink.net could not resolve.
I also was able to bind a socket on port 53. What API were you using that returned SLNETERR_BSD_EADDRNOTAVAIL?

Best regards,
Sarah

Hi Sarah,

the out_of_box example works fine as you say.

I am not sure how you tested to stop the DNS, because that is not inside the out_of_box example, right ?

My code is the following; (please not that for clarity of reading I took out a lot of error handling here)

// boot rountine at startup...
if (sl_Start(0, 0, 0) < 0) { /*removed*/ }  
if (sl_WlanSetMode(ROLE_AP) < 0) { /*removed*/ }
if (sl_Stop(0) < 0) { /*removed*/ }
if (sl_Start(0, 0, 0) < 0) { /*removed*/ }

// some other startup config API calls, taken over from example code in "network_terminal" example 

// try to disable the DNS server which is running on port 53
//if (sl_NetAppStop(SL_NETAPP_DNS_SERVER_ID) < 0) { /*removed*/ }  // <-- this FAILS
if (sl_NetAppStop(SL_NETAPP_MDNS_ID | SL_NETAPP_DNS_SERVER_ID) < 0) { /*removed*/ }   // <-- this WORKS

// For changes to take affect, we restart the NWP
RetVal = sl_Stop(0xFF);
ASSERT_ON_ERROR(RetVal, DEVICE_ERROR);
RetVal = sl_Start(0, 0, 0);
ASSERT_ON_ERROR(RetVal, DEVICE_ERROR);

//...

// try to run a server on port 53
s = sl_Socket(AF_INET, SOCK_DGRAM, SL_IPPROTO_UDP);
if (s < 0) { /*removed*/ }
memset(&localAddr, 0, sizeof(SlSockAddrIn_t));
localAddr.sin_family = AF_INET;
localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
localAddr.sin_port = htons(DNSPORT);
status = sl_Bind(server, (SlSockAddr_t *)&localAddr, sizeof(SlSockAddrIn_t));
if (status < 0) { /*removed*/ }    // <-- THIS LINE GIVES error -99 (SLNETERR_BSD_EADDRNOTAVAIL) when I use port 53

If I use port 54, then it works fine. My conclusion is thus that the DNS server is still running.

Are you using the same versions as I do ? I am using the latest SDK (2.20) and latest ServicePack.

Could you post your test code that show how it works for you ? Perhaps there is another API call that you used when setting up the NWP ?

BR,

Salvatore