ESP32 Forum

Posted: **Wed Nov 21, 2018 12:09 am**

I'm building off the softAP example code, and I'd like my AP to act as a DNS server so a client can resolve the device by name.

It looks like there are some options to set hostname and DNS functionality via LWIP, but I can't get them to work with a client. For example, here's some code that might go after the wifi start call:

Code: Select all

ESP_ERROR_CHECK(esp_wifi_start());

// ...later...

const char * hostname;
tcpip_adapter_ip_info_t ip;
uint8_t param = 0;

ESP_ERROR_CHECK(tcpip_adapter_dhcps_stop(TCPIP_ADAPTER_IF_AP));

ESP_ERROR_CHECK(tcpip_adapter_set_hostname(TCPIP_ADAPTER_IF_AP, CONFIG_ESP_NETNAME));

ESP_ERROR_CHECK(
    tcpip_adapter_dhcps_option(
        TCPIP_ADAPTER_OP_SET,
        TCPIP_ADAPTER_DOMAIN_NAME_SERVER,
        &param,
        sizeof(param)
));

ESP_ERROR_CHECK(tcpip_adapter_dhcps_start(TCPIP_ADAPTER_IF_AP));

If param is set to 0, then a Windows 10 client gives:

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> nslookup streamer
DNS request timed out.
    timeout was 2 seconds.
Server:  UnKnown
Address:  192.168.4.1

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to UnKnown timed-out

If it's set to 1, then:

Code: Select all

>nslookup streamer
Server:  UnKnown
Address:  0.0.0.0

*** UnKnown can't find streamer: No response from server

When param = 1 I also don't get any DNS servers on the client via DHCP, which seems like it's the opposite of what a 1/0 flag should be.

Do I need to know the domain here? How is it set? I'd prefer not to use mDNS because it introduces extra dependencies for Windows clients. Is there a way to get normal DNS working out of the box with the IDF?

ESP32 Forum

Does the IDF provide a DNS server? How do I use it?

Does the IDF provide a DNS server? How do I use it?