How can I stop/locate specific internal IP addresses?

Posted on 2006-05-03
Last Modified: 2010-03-18

I used the DHCP utility on my firewall to determine that a .35 and .105 are downloading a lot, maybe a virus or maybe yahoo launch or something.  I would like to find those computers in our network, but unfortunately when I do a DNS lookup on our DNS server those addresses are not listed.  .100 and higher is for DHCP, while under .99 is static (so that should be easier to find, right?).  Is there a way to block specific IP addresses from doing anything, or way to locate them or what they are doing? (tools, etc).

Question by:youthworks
    LVL 3

    Accepted Solution

    You should be able to use your firewall rules to block all access to/from those IP's... believe me, the users on those machines will contact you soon!  What kind of firewall do you use?  Be careful with the static address though, it could be an important server or other device.
    LVL 21

    Assisted Solution

    Try this, it can scan those IPs and give you back info on the computer including the name.  This may help you find your offenders.

    On a MS Network it's a good idea to run MS DHCP service instead of using your firewall for DHCP.  With DDNS enabled on the DHCP server, DNS will be registered by the DHCP server when it hands out an address instead of relying on all clients to update themselves in DNS.

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