ESP8266 Community Forum

Posted: **Sat Dec 02, 2017 9:56 am**

I'm trying to not use static ip addresses for my MQTT server by using the hostByName.

When I use the command to get the ip address of an external (nttp) server, the command returns the ip address of the server just fine, but when I use the same command to get an ip address of a host on my LAN, it fails to get the ip address.

Here my code:

const char* mqttServerName ="servername";
IPAddress mqttServerIP;

WiFi.hostByName(mqttServerName, mqttServerIP)

What did I do wrong?

Thanks
bdollerup

Posted: **Sat Dec 02, 2017 6:42 pm**

Do you have a DNS or Bonjour running inside your LAN? :idea:

Posted: **Sat Dec 02, 2017 6:57 pm**

External names are resolved by external DNS servers. What is inside your private network is not available to external servers so you need to add a mechanism in your network for that to work.

For Mac OSX support is built in through Bonjour already.
For Linux, install Avahi.
For Windows, install Bonjour.

Posted: **Sat Dec 02, 2017 7:54 pm**

https://github.com/esp8266/Arduino/issues/3087

It seems that hostByName does not make use of mDNS.

ESP8266 Community Forum

Using WiFi.hostByName() on LAN to get Server IP address

Using WiFi.hostByName() on LAN to get Server IP address

Re: Using WiFi.hostByName() on LAN to get Server IP address

Re: Using WiFi.hostByName() on LAN to get Server IP address

Re: Using WiFi.hostByName() on LAN to get Server IP address