topic DHCP DORA Process stucks at DISCOVER/OFFER in i.MX Processors

DHCP DORA Process stucks at DISCOVER/OFFER

Muthyam — Mon, 18 Nov 2024 12:09:17 GMT

Hello Community,

I’m using the Apalis iMX8 QuadPlus with Yocto Dunfell on our custom board. While the unit generally functions well, there are times when it fails to obtain an IP address from the DHCP server. We’ve used tcpdump on both the server and client sides for analysis. The client continuously sends DHCP Discover packets, which the server receives and responds to with DHCP Offer packets. However, these Offer packets are not visible on the client side. As a result, the client keeps sending additional Discover packets, causing the process to stall and preventing it from acquiring an IP address. This situation persists until the unit is power-cycled or the eth0 interface is brought down and then back up.

Client Side

Client_Broadcasting_DISCOVER_Message1366×768 69.4 KB

Server Side

Server_Replying2Discover_OfferWithUnicast719×678 15.1 KB

Any guidance on resolving this issue promptly would be greatly appreciated.

Thank you,
Muthyam D.

Re: DHCP DORA Process stucks at DISCOVER/OFFER

JosephAtNXP — Mon, 18 Nov 2024 14:12:26 GMT

Hi,

Thank you for your interest in NXP Semiconductor products,

Have you tried to replicate with the latest BSP for your board? Is the issue still present?

Regards

Re: DHCP DORA Process stucks at DISCOVER/OFFER

Muthyam — Mon, 18 Nov 2024 14:21:23 GMT

Hi,

I have not tried with the latest BSP, as this issue is occurring with units already deployed in the field. We need to address this problem without changing the BSP version.

Regards,
Muthyam D.

Re: DHCP DORA Process stucks at DISCOVER/OFFER

JosephAtNXP — Tue, 19 Nov 2024 21:46:41 GMT

Hi @Muthyam,

The workaround you can use is to add the following line to your /etc/network/interfaces:

auto eth0 iface eth0 inet dhcp dhclient_opts -nw

Regards,

Re: DHCP DORA Process stucks at DISCOVER/OFFER

Muthyam — Wed, 20 Nov 2024 13:55:35 GMT

Hello @JosephAtNXP ,

As far as I know, the /etc/network/interfaces file is used when NetworkManager manages the network interfaces. However, the Toradex BSP provides two utilities for network configuration: ConnMan and systemd-networkd. By default:

The Ethernet port is managed by ConnMan.
The USB RNDIS interface is managed by systemd-networkd.

In our setup, there was no /etc/network/interfaces file by default. After encountering this issue, we disabled the ConnMan service and assigned control of the eth0 interface to systemd-networkd.

Even after manually adding an interfaces file at /etc/network, the issue still persists.

Thank you,
Muthyam D.