WIZ110SR(ver4.31) continued discharging a large quantity of packets to


I use WIZ110SR now.
Yesterday, the Internet communication in Our office became very slow.
I thought the beginning whether it was a temporary thing, but was not improved even if several hours passed.

I started Wireshark with my PC.
Then my PC received it a large quantity of packets.
When I checked the details in Wireshark , two terminals having the local IP always sent a packet about DHCP for Distination
Furthermore, I understood that it was WIZ110SR from two Mac addresses.

After Reset on two WIZ110SR , this packet disappeared, and internet communication became safely nomal.
Two WIZ110SR’s firmware is Ver4.31.

When I see an update history of the WIZ110SR’s firmware, there is the following sentence in Ver5.10.

“Fixed the Search error at the DHCP or DNS fail”

Are this document contents same as this phenomenon?

Please tell me the best way for this phenomenon.