Detecting anonymous DHCP server

I have a customer who have a weird issue. All of a sudden most of the PC clients started to get their IPs from an unknown DHCP Server which we know it's not a machine as it doesn't show any MAC address when we tried to filter the traffic using Wireshark.

How do we get this DHCP server and find out where it is?

LVL 24
Mohammed HamadaSenior IT ConsultantAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Tony GiangrecoCommented:
That sounds like a virus or hacker has infiltrated your network. I'd read this post to see if it helps.
I had this problem a while ago.  It was a user that had bought in a router to use as a CAT5 hub.  Unfortunately, he hadn't switched off DHCP on it.  As a result it was distributing IP addresses.

Unfortunately, its a matter of checking all the ports to see what's plugged in.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Mohammed HamadaSenior IT ConsultantAuthor Commented:
That's exactly what was the problem. it was a dhcp server
Great stuff.  Glad you found it.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.