[lwip-users] failed to resolve dns

[Bas Prins]

Hi,

I am trying to use the DNS lookup in the http client but lwip tells me it failed to resolve hostname.

I am using the following code

ip_addr_t dns_ip;

IP4_ADDR(&dns_ip, 8, 8, 8, 8);

dns_setserver(0, &dns_ip);

_settings.result_fn = DownloadFinshedCallback;

LOCK_TCPIP_CORE();

err_t err = httpc_get_file_dns(

"http://www.google.nl",

8000,

url,

&_settings,

HttpPacketReceivedCallback,

this,

nullptr);

UNLOCK_TCPIP_CORE();

8.8.8.8 is a DNS server from google. I also tried the actual DNS server from my provider. Both result in the same behavior.

Which gives the following logging output:

[21:27:33:731] dns_enqueue: "http://www.google.nl": use DNS entry 0␊

[21:27:33:735] dns_enqueue: "http://www.google.nl": use DNS pcb 0␊

[21:27:33:741] dns_send: dns_servers[0] "http://www.google.nl": request␊

[21:27:33:746] sending DNS request ID 23300 for name "http://www.google.nl" to server 0␍␊

[21:27:33:751] pppos_netif_output[0]: proto=0x21, len = 66␊

[21:27:33:754] [Download] : Downloading file from server...␊

[21:27:33:894] pppos_netif_output[0]: proto=0x21, len = 40␊

[21:27:33:958] tcpip_thread: PACKET 0x20018f4c␊

[21:27:33:962] pppos_input[0]: ]: got 11 bytes␊

[21:27:33:962] tcpip_thread: PACKET 0x20018f4c␊

[21:27:33:967] pppos_input[0]: got 64 bytes␊

[21:27:33:968] tcpip_thread: PACKET 0x20018f4c␊

[21:27:33:972] pppos_input[0]: got 57 bytes␊

[21:27:33:973] pppos_input␊

[21:27:33:975] ppp_input[0]: ip in pbuf len=126␊

[21:27:33:977] dns_recv: "http://www.google.nl": error in flags␊

[21:27:33:981] httpc_dns_found: failed to resolve hostname: http://www.google.nl␊

I can download files using http_client fine when I just hard code the IP addresses. Is there anything fundamentally wrong with what I am doing?

Any tips maybe to help me on my way?