LwIP not completing the DORA-DHCP schedule

[GStou]

Added "DHCP" in the title to give the context.

Using an STM32H7S78-DK I try to set up the network to join an IPv4 network through DHCP.

I did set up the board using CubeMX, standard configuration, MPU activated.

FreeRTOS + LwIP

Removed all other interfaces I don't need.

Made sure the Ethernet clock shows 50MHz

The LED's on the RJ45 start to blink (Orange LED blinks with packets exchanged)

but I get no IP address.

digging in the possibilities I added a simple routine to monitor the DHCP advancements.

 struct dhcp *dhcp_data = netif_dhcp_data(&gnetif);
	 if (dhcp_data != NULL) {
	 printf("[DHCP] State: %d, Retries: %d\r\n", dhcp_data->state, dhcp_data->tries);
	 }

this shows I get stuck in state 6: waiting for an ACK

-> what could be behind this?

can someone share an .ioc file that sets everything correctly in MX?

[mƎALLEm]

Hello,

What do you mean by "DORA" in the title?

[GStou]

Discover

Offer

Request

Acknowledge

The packet exchange procedure of the DHCP proces

[STackPointer64]

Hello @GStou,

First things first, could you please answer the following questions to help me better understand the issue?

• Have you tried capturing the network traffic using Wireshark?
• Was an ARP announcement packet sent?
• Are you certain that your DHCP server is functioning correctly?
• Could you also attach your STM32CubeMX configuration (.ioc file) so I can review it?

Best regards,

[GStou]

I tried to reproduce the situation, as I was not trusting the waiting for ACK situation.

If true, the IP address should have been listed on the router DHCP server.

Now the board doesn't even identify the presence of the Ethernet cable anymore. LED's are on.

LED's could simply be the driver chip identifying the electric status of a connected Ethernet cable.

Can it be that I changed bit's on the board/µC that make things go bad?

Settings that remain over reprogramming?

[STackPointer64]

Hello @GStou,

Have you tried inspecting the following project available in our GitHub repository? Please focus on the LwIP configuration and the DHCP implementation in the application, as the issue may be related to a misconfiguration in DHCP or the descriptors:

• STM32H7S78-DK/Applications/LwIP/LwIP_TFTP_Server

Best regards,

[Andrew Neil]

Some LwIP debug/diagnostic tips/resources:

https://community.st.com/t5/stm32-mcus-products/lwip-ethernet-in-stm32h7-working-in-stm32cubeide-but-not-in-iar/m-p/748501/highlight/true#M267524