WIZnet Developer Forum

DHCP protocol not being followed

We have ~300 WIZ108SR running on a network using DHCP. We are using some combination of HW 1-1 with FW v2.20 and HW 1-2 uses FW v4.04. Our settings are:

Baud Rate 115200
DHCP enabled
Debug Messages disabled
Data bits 1
Parity 0
Flow 0
Stop bits 0
Timeout 60

The issue we are having is the wiznet devices are discovered by the DHCP server, offered an IP address reservation but fail to request from the DHCP server and so never receive an acknowledgement. We end up with all of these devices making these requests continuously. We are concerned it is disrupting other critical parts of our network. We have other instruments and computers running DHCP on this network and they do not have this issue so we strongly believe it is related to the wiznet implementation of DHCP.

Hi, bbaker.
How many clients on your same private network?
And, Did you check the available IP pool range of DHCP server assigned?

Please capture the your network packets by Wireshark program and attach the save file (.pcapng) on this post.
We will review your packet capture and reply results.

Attached is a sample of the DHCP requests.
All of the devices we have in the lab receive an IP address from the DHCP server the issue is they are not completing process through authentication so they are continuously being discovered. We have sufficiently long reservations that they are not dropping their IP address but it is causing unnecessary stress on the system and is likely causing problems elsewhere in our system. 24 out of ~300 wiznet are working correctly. They are a combination of v1.1 hardware with 2.20 firmware and v1.4 hardware with 4.04 firmware.
Active DHCP Leases.xlsx (9.68 KB)
DHCP Requests.xlsx (9.66 KB)

Hi, bbaker.
I’m sorry for late reply.
We are looking to the cause of your problems, so I made DHCP modified version firmware for hardware Rev. 1.1 (fw v2.21) for you.

The cause of the problem is estimated to be duplicates of DHCP Transaction ID (XID). Therefore, the Modified firmware’s transaction ID to be different for each module based on MAC address. And DHCP server and the DHCP client has been modified to exchange packets via broadcast transfer mode.

You can check and review the DHCP packet transaction using WireShark program on your monitoring PC.

I’ve attached modified firmware.
Please reply after the test. (If possible, please reply with the WireShark packet captures)

[Note] This firmware is ONLY for the old revision devices (Rev 1.1)

WIZ108SRv2_21_Preliminary.zip (19.2 KB)

We are staging the update but so far it appears to have resolved this issue with the Rev 1.1 hardware. I will update you when we have completed the updates.

We removed this firmware from our lab. Once we started installing it on active communicating equipment we started having issues that required factory reset before it would communicate again. We could establish a connection but no other communications could be made. This was happening on all units in less than 24 hours on >90% of the equipment we updated.

Any progress we are back to the released firmware because of the errors the beta firmware caused.

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