Have any of you had this happen?
We’ve got a customer, who will take all spare IPs.. like, 100 of them.. I can’t find a reason, so I just shut him down.
Even if I turn the router to “static” only, he’ll still take everything.
Virus?
Ideas?
what do you mean take all IP’s User who is connected to router got IP’s or the router it self grabs all of them from DHCP ?
and if user → does User MAC change for all IP’s ? in “Leasses” section
User’s router connects to our router.
User’s router takes all vacant IPs.
User’s MAC is the same for all IPs.
(Even if I set to “static”, still happens.)
The only way to stop it, is to turn off the users radio.
(Disconnect them from my network.)
Where is this user located, in the same building as you? How is he connected, wired or wireless?
Why is he a) useing another router and b) why does he need all the IP’s?
If he is using another router, then he should be passing out IP’s from that router and not yours.
For the most part, there is no easy way to turn off IP’s directed just to him unless you do some reconfiguation in your router.
What router are you using? Does it have at lest two user either ports? If it does and he is connected by wire there is a way to just assign one IP to him.
If he is connected wireless then that is a problem.
Good Luck
5 miles away. 
He doesn’t need them, that’s just it. His router is just taking them and he claims no knowledge as to why.
(This is a problem, not a plan..)
At that site, it’s a 493G.
I’m not really concerned with our set up, it’s SOP for a WISP and don’t have anything like this happening anywhere else.
It’s just this one customer’s router, and I want to try to figure out what’s causing it.
How is the RB493G configured? Does it have its own dhcp server set up on the LAN interfaces? Is it using a masquerade or routed?
I always recommend enabling dhcp debug logging to see exactly what is happening. In your dhcp server router that is issuing the ips, use this.
/system logging
add topics=dhcp,debug action=memory