How can I prevent some computers to 1

[Salibas]

How can I prevent some computers to use the DHCP server and get a lease IP. I have computers on my lan that should not take any IP from my DHCP and get into my subnet. I dont have any control on those computers whatsoever.

 

[Digga]

Hi Salibas,

you could give them a fixed IP. Digga

Sharing Knowledge Saves Valuable Time!

 

[Salibas]

Thank you

but, I dont have any control on those computers. My ISP shares the same network with all his clients. I used a router to isolate my small company network, but no use. Other people are still getting IPs from my DHCP.

 

[w1nn3r]

Are you running a wireless router or are people physically breaking into your location to plug into your LAN or how exactly are they pulling an IP from your DHCP server?

 

[Salibas]

The situation is like this:

our local ISP uses a WAN to distribute iternet connection using the subnet 192.168.*.*, and our office is using one IP of this subnet to connect to out ISP. I am using a router to "hide" my network from my ISP network and I use the subnet 10.154.*.* . So, as you can see, there are many users on my ISP network who I dont have any relation with them.

 

[dikv]

geef ze een vast ip adres en zet de lease vast in je dhcp server

 

[ashpp]

If other people on the WAN can get an IP address from your DHCP server it means that a) Your ISP has no blocking/rules or firewalling and b) Neither do you.

Either...

Get a firewall or block all incoming DHCP ports on the router. My suggestion is to get a firewall ASAP, it looks like anyone can easily 'route' through your router and access your server.

Ash.

 

[Davetoo]

Get and install a firewall yesterday!

Having systems obtain an IP address from my DHCP server that aren't in my network would be the least of my worries! It's just the symptom of a bigger problem. Your server(s) is(are) visible to your entire ISP's WAN, from what you've said.

That's not good.

Dave