We have a multitude of Dell OptiPlex models in our organization. We are setting up WOL and all our devices. We are having an issue with OptiPlex 790 and 990 only. All other models, 7040, 9010, 9020, 9020m are not having this issue.

The issue is when the 790 and 990 goes to sleep. After the 4hrs - 240 minutes arp counter (Default cisco arp timeout) the switch sends a arp request to validate if the workstation is still connected or not. If connection is valid, the counter comes back to zero minutes and will do the same thing again at the next 240 minutes. For the 790 and 990, the connection is never valid after 4hrs and the entry is erased from the arp table making WOL impossible. For all our other models, the entry stays in the arp table and are able to WOL.

Optiplex 790, 990 and 9010 have the same NIC models and the 9010 stays in the arp table without any issues. So for testing, I have also installed a DLINK NIC in the 790-990 and I got the same result. All the NIC settings, Bios settings and windows base image are identical on all the optiplex models. My link light on the NIC are flashing when in sleep mode and my bios are all up to date. Any clue why the 790-990 are not staying in the arp table?

Thanks in advance!