Mac address conflict on user machine due to mac address of VLAN 1

[amit.rane]

Hi All,
I am facing strange DHCP conflict issue .Users are getting IPv4 address conflict on their systems frequently. Upon check the details (Microsoft error code 4199) i observed that all the users are getting conflict with different IP's but same MAC address. After digging the issue further i found that conflicting mac address is of VLAN 1 of our switch.

Has anybody faced such issue? Kindly provide your valuable inputs.
Thanks in advance.

Regards,
Amit Rane.

[devils_advocate]

Could be an issue with Proxy ARP

Under the VLAN1 SVI, disable proxy arp.

Thanks

[amit.rane]

i

[Reza Sharifi]

Hi,

If this is the case create a different vlan (vlan2) and move some users to it and watch for the same error message.  That will tell you if the issue is really vlan1 MAC address.

HTH
 

[amit.rane]

Thanks for your inputs.

This is the last option we can use as it will include downtime as well as assigning all the ports in access switches in new VLAN.