RE: IP address allocation

From: Brad Hill - Quonic (brad_at_quonic.com)
Date: 07/31/03

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    To: <security-basics@securityfocus.com>
    Date: Thu, 31 Jul 2003 12:06:46 -0400
    
    

    It may depend on the kind of ISP you're dealing with. DSL/Cable
    providers seem to assigning generic DNS entries such as
    host01.client.com, host02.client.com, etc for every IP address in a
    block. I believe most ISP's offering leased lines will do the same
    however they will usually change the DNS entries if requested. The
    alternative would be to manage your own DNS.

    To answer your question more directly: Yes, most ISP's will assign
    generic DNS entries for all IP's in a block regardless of whether or not
    they are currently in use.

    __
    Brad Hill
    brad@quonic.com

    > -----Original Message-----
    > From: Terry [mailto:tech@futurecourse.com]
    > Sent: Thursday, July 31, 2003 5:41 AM
    > To: security-basics@securityfocus.com
    > Subject: IP address allocation
    >
    > Hi,
    >
    > I've googled but haven't really come across anything that answers my
    > questions. Is it common practice for ISPs to allocate a block of
    > addresses to a customer and put in DNS records for ones that are
    > unused?
    >
    > For example, xxx.8-xxx.15 is assigned to the customer. Customer uses
    > xxx.9 for the router and xxx.10 for web server. xxx.11-14 are unused.
    > I would expect to see DNS records for xxx.9 and xxx.10 but not for the
    > rest of the block. Am I wrong? If there are DNS records for the rest
    > of the IPs, why is that? Is there some security reason for doing
    > this?
    >
    > --
    > Regards,
    > Terry
    >
    >
    >
    ------------------------------------------------------------------------

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    > -
    >
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    > --
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