Security Basics mailing list archives

DHCP replies ?


From: Netops <michael () bluesuperman com>
Date: Tue, 20 Sep 2005 22:14:39 -0600

Hello,

I have created a script that monitors DHCP replies on a network. Run from cron every X, it will send out a DHCP request and wait up to 30 seconds for DHCP replies.

It then compares the replies and creates a checksum. If the checksum ever differs it sends a notification via e-mail with a small report.

Now it works great except that is appears some times out windows DHCP server will send a reply missing some options.

For example a standard reply on the network has the following information:

client IP address
name servers
default route
net mask
server id
broadcast
domain name

But once in a while a DHCP offer will show up containing only the following information:

client IP address
default route
net mask

I am assuming this would be caused by the client not requesting all that information ? Does any else know of anything like this ?

Michael


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