From: King, Michael (MKing@bridgew.edu)
Date: Wed Oct 03 2001 - 12:01:19 CDT
I have a small perl script that I got off the ISC DHCP list that I use to
tell me how many leases are used in a subnet, if you want it to look at.
It's called clease.pl
-----Original Message-----
From: King, Michael [mailto:MKing@bridgew.edu]
Sent: Tuesday, October 02, 2001 5:31 PM
To: 'netreg@southwestern.edu'
Subject: RE: NetReg: Force use of DHCP server vs picking your own
manually
I'm grasping at straws, since I don't understand it myself, but couldn't
OMAPI (OMSHELL is the interface I believe) be used to provide this? I know
you wanted you start investigating OMSHELL for version 2.0
Here's a snippet from the man OMSHELL command
<Snip>
VIEWING A REMOTE OBJECT
To query a lease of address 192.168.4.50, and find out its
attributes, after connecting to the server, take the following steps:
new lease
This creates a new local lease object.
set ip-address = 192.168.4.50
This sets the local object's IP address to be 192.168.4.50
open
Now, if a lease with that IP address exists, you will see all the
information the DHCP server has about that particular
lease. Any data that isn't readily printable text will show up in
colon-separated hexadecimal values. In this example,
output back from the server for the entire transaction might look
like this:
> new "lease"
obj: lease
> set ip-address = 192.168.4.50
obj: lease
ip-address = c0:a8:04:32
> open
obj: lease
ip-address = c0:a8:04:32
state = 00:00:00:02
dhcp-client-identifier = 01:00:10:a4:b2:36:2c
client-hostname = "wendelina"
subnet = 00:00:00:06
pool = 00:00:00:07
hardware-address = 00:10:a4:b2:36:2c
hardware-type = 00:00:00:01
ends = dc:d9:0d:3b
starts = 5c:9f:04:3b
tstp = 00:00:00:00
tsfp = 00:00:00:00
cltt = 00:00:00:00
As you can see here, the IP address is represented in hexadecimal, as
are the starting and ending times of the lease.
<end snip>
Granted, a loop to process that would be time intensive, since you are
accessing a server in real-time rather than grep'ing a flat text file. Plus
the time appears to be hexadecimal, rather than readable.
Michael
-----Original Message-----
From: Peter Valian [mailto:valianp@southwestern.edu]
Sent: Tuesday, October 02, 2001 2:32 PM
To: netreg@southwestern.edu
Subject: Re: NetReg: Force use of DHCP server vs picking your own
manually
I agree. The problem I foresee is with the leases file...it keeps more
than *active* leases...perhaps a routine to see if the current time is
within the start and end times would suffice.
King, Michael wrote:
>Personally, My students move so much, the subnet they register in, is not
>the subnet they are in the following week.
>
>I would find most usefull how many address, (leases) are currently active
in
>the given subnet. That was I know if I'm about to run out of address or
>not.
>
>-----Original Message-----
>From: Peter Valian [mailto:valianp@southwestern.edu]
>Sent: Monday, October 01, 2001 5:43 PM
>To: netreg@southwestern.edu
>Subject: Re: NetReg: Force use of DHCP server vs picking your own
>manually
>
>
>True. however, Im rethinking the usefulness of that overview. That
>displays the subnet the user was on when they registered...not where
>they are currently.
>
>I don't know...would it be more or less useful to have the overview
>display the current address allocation rather than where they registered
>from?
>
>thoughts?
>
>-peter
>
>King, Michael wrote:
>
>>But if you do that, you run into the same problem I have.
>>
>>Doing this will "break" (term used very loosely here) Subnet overview.
>>Subnet overview was built (I think) with the assumption that the
>>Unregistered range would be in the same subnet as the Registered range.
>>
>>-----Original Message-----
>>From: John Hascall [mailto:john@iastate.edu]
>>Sent: Friday, September 28, 2001 9:40 AM
>>To: netreg@southwestern.edu
>>Subject: Re: NetReg: Force use of DHCP server vs picking your own
>>manually
>>
>>
>>
>>>I think I get the idea now. I suppose ideally in addition to blocking
>>>the non registered addresses, you'd keep the ip domain for registered
>>>users with-in a few hundred addresses of your actual number of users to
>>>maximize the chance that the dhcp server will try to use it. So you can
>>>find out and yell at them.
>>>
>>>Further more, you could make your addressing system harder to figure out
>>>by choosing more random smaller chunks of the address space in the
>>>registered and unregistered pools. So, rather than 172.16.2.0-->
>>>172.16.4.0 is unregistered and 172.16.5.0--> 172.16.8.0 being registered
>>>addresses, something more like:
>>>
>> Actually using a non-routable (reserved for local LAN) address range
>> for your unregistered users is best.
>> For example:
>>
>> pool {
>> range 10.11.20.1 10.11.20.199;
>> allow unknown clients;
>> deny dynamic bootp clients;
>> min-lease-time 300;
>> default-lease-time 600;
>> max-lease-time 1200;
>> option domain-name-servers netreg-1.ait.iastate.edu;
>> }
>>
>> pool {
>> range 129.186.21.1 129.186.21.199;
>> deny unknown clients;
>> deny dynamic bootp clients;
>> ddns-updates on;
>> }
>>
>> You will never route 10.x.y.z past your (campus) border router.
>>
>>John
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>
-- Peter Valian Network & Systems Administrator Southwestern University Georgetown, Texas 512.863.1586 office 512.863.1605 fax --********************************************************************** To unsubscribe from this list, send an e-mail message to majordomo@southwestern.edu containing a single line with the words: unsubscribe netreg Send requests for assistance to: owner-netreg@southwestern.edu ********************************************************************** ********************************************************************** To unsubscribe from this list, send an e-mail message to majordomo@southwestern.edu containing a single line with the words: unsubscribe netreg Send requests for assistance to: owner-netreg@southwestern.edu ********************************************************************** ********************************************************************** To unsubscribe from this list, send an e-mail message to majordomo@southwestern.edu containing a single line with the words: unsubscribe netreg Send requests for assistance to: owner-netreg@southwestern.edu **********************************************************************
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