Hello All,
It is possible that the router is performing some sort of DHCP function.
If this is a AD domain with the MS DHCP server authorized, look in the
DHCP logs for the days that you have this problem and see if you can find
anything with code 50 and above. If you do, look at the IP address for the
rogue DHCP server.
Additional Resources
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298367 How to Monitor the DHCP Log File
http://support.microsoft.com/?id=298367
Shane Brasher
MCSE (2003,2000,NT),MCSA Security, N+, A+
Microsoft Platforms Support
Windows NT/2000 Networking