STM32f4 LwIP MQTT

[voyvoda .]

Hello,

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I am able run successfully mqtt example on my stm32f4 MCU ​and on my local network.

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I want to run the same code on a cloud platform. However there is a link provided by mqtt cloud pro​vider not an IP address like 192.168.0.10

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Can I directly use the below link instead of the IP address ? If not, then How can I ?

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1f87a053302042c7a0ccb2dac5d1263b.s1.eu.hivemq.cloud

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B​est Regards

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[Vangelis Fortounas]

hello

This issue covered here.

In general, dns_gethostbyname() and dns_gethostbyname_addrtype() functions resolve hostname (hivemq.cloud) to address

[voyvoda .]

@Vangelis Fortounas​  Thank you for your reply. I can only use dns_gethostbyname() with socket or netconn. So I need to use freertos. Is there any other way to use with RAW API functions ?

Or I migth use the web site http://domaintoipconverter.com/index.php to get the IP address directly.

In addition, How can I subscibe to a topic with lwip mqtt example.

I want to use second STM32 board to subscribe to the topic. In short, one board will publish and the other will subscribe(receive). "hivemq.cloud" will be the broker.

[Piranha]

Those functions are parts of RAW API. Read the documentation:

https://www.nongnu.org/lwip/2_1_x/group__dns.html

[Vangelis Fortounas]

Hello

try to use as DNS server the default router's address or the gateway address that is set during initialization (netif_set_addr(..))

If dhcp is enabled , there is no need to set a DNS address

[voyvoda .]

Hell @Vangelis Fortounas​ I am using static IP address.

Can you be more specific ? I did not understand what you mean.

[Vangelis Fortounas]

Hello

Somewere in code, static address was set by calling netif_set_addr(...) function.

This function takes three parameters, static IP address, subnet mask and gateway(GW). (in cubeMX these parameters are set sequentially).

Usually the GW address is the IP address of the router that Ethernet cable is connected, also is the default DNS address. (eg 192.168.1.1).

I suggested to put as DNS server address (dns_setserver(...)) the default address of the router that is probably used also as gateway address.

I wrote "probably" because i don't know the exact network topology.

[TG.3]

Hello @voyvoda .,

I tried to connect to MQTT server using LWIP protocol from STM32F4. I am able to connect but getting authentication failure in MQTT server side. And, not able to publish the date to the server. Kindly help resolve this issue.

[SDu T]

Good day

Have you been able to solve the problem? I know it is  a long time ago, but any possibility of code sharing?

Or even a link to working software. I am using the STM32H563Z