DHCP Scopes and Scope Options Import & Export

I need to adjust lease times for over one hundred scopes spread across multiple servers (about half of them are on one server, though). There will be 2 or 3 different lease times used. What is the best way to do this?
I know I can use netsh to change the option for each scope. But I would like to script the collection of the list of scopes, rather than typing the list manually. Is there a way to export a list that contains just scopes and descriptions?
Thanks

Hi,
Actually, it can be exported as txt file.
netsh dhcp server export c:\DHCP\myscopes.txt
Export-DhcpServer
And you can also manage it via powershell
Use the PowerShell DHCP Module to Simplify DHCP Management
http://blogs.technet.com/b/heyscriptingguy/archive/2011/02/14/use-the-powershell-dhcp-module-to-simplify-dhcp-management.aspx
Hope this helps.

Similar Messages

DHCP scope options: How TO

Hi,
I have a 10.4 server as DHCP for several VLANs. I need to setup DHCP scope options on two VLANs to be able to direct DHCP requests from a specific device (IP phones) to the relevant VLAN for obtianing IP addresses.
I cannot see bootpd.plist in /etc and not much information available online about this.
Found these two relevant posts but not much of help:
http://discussions.apple.com/message.jspa?messageID=7200952
http://discussions.info.apple.com/message.jspa?messageID=5054131
I can export the serveradmin settings out and can see the entries but where and how do I make the scope entries? plist editor won't open the file and if i convert to csv in excel the existing data is there and logical but where do i enter my scope options?
any help in the right direction will be much appreciated.
cheers
Muhammad

You didn't try hard enough... ;). You need to use the Get-DhcpServerv4OptionValue cmdlet (or ...v6...).
Get-DhcpServerv4OptionValue -ComputerName <computername> | Where-Object OptionID -eq 6 | Select-Object Value
Edit: I think it's important that you know how I solved this problem. Perhaps you can put it to use yourself some time. The first thing I did was return all the 'get' DHCP cmdlets using this command: Get-Command -Module dhcp* -Name get-*. I quick scanned
the cmdlets (actually, they're functions) and found the word 'option.' I jumped over to the DHCP MMC snap-in and quickly figured out why that sounded familiar. In the GUI, you right-click Server Options to get to this setting. I then ran the function in my
example without piping it to the Where-Object cmdlet, and it return a value property. I then added the | Where-Object to filter down what was returned.
In writing this edit, I determined there's actually an -OptionID parameter, which means I could have better written my example. Here's that now:
Get-DhcpServerv4OptionValue -ComputerName <computername> -OptionID 6 | Select-Object Value
Always filter as close to the left as possible. That's means we don't want to pipe to something when we can filter with a built-in parameter.

DHCP Scope Options for PXE on swtiches

Hello,
I am trying to get PXE support for OSD in a sccm 2012 environment.
WSD resides on the same server as my SCCM 2012 Primary server.
I currently have one dp with PXE enabled.
My networking team asked what I needed for PXE support.
I responded:
DHCP discover package contains option 60
DHCP discover uses port 67 UDP
DHCP Offer uses port 68 UDP
Server ack from PXE server including options 66 and 67
Client unicast request for options 66 (boot server) and option 67 (boot file) (port 4011 UDP)
They responded with what do I need from below
The above response
was from a different job and location. Now they are asking for info on boot file and hostname. Hostname I would think be the dp or in our case, the sccm primary server. The boot file, I have no idea
Thanks so much for your help,
Mark

Ok, networking agrees to use IPhelpers, but needs "official documentation" of exactly what to do. Does anyone have a link that I may give to network to use. I really do appreciate it. I never thought I would have to do the network
part for them. :(
Thanks,
Mark
The general gist is that your router interfaces need to relay/forward bootp/dhcp "discover" & "request" to *both* your DHCP and your PXE-enabled DP.
This will cause the DHCP-client's discover/requests to be relayed to both, but the PXE-enabled DP won't respond to the initial discover/request because it can't issue IP addresses.
But once the client *does* have an IP address, and it issues a PXE request, the PXE request will be relayed to both, the DHCP server will ignore it but the PXE-enabled DP will process it and offer the NBP and then the TFTP of the boot image etc.
This is recommended/preferred over using DHCP options 66/67.
It's recommended in lots of places, but here's a great reference:
http://blogs.technet.com/b/system_center_configuration_manager_operating_system_deployment_support_blog/archive/2011/10/14/troubleshooting-the-pxe-service-point-and-wds-in-configuration-manager-2007.aspx
For "official documentation" on how to configure the router, the router manufacturer will help with that.
Cisco refer to their implementation as "ip helper-address", which is why the feature is often referred to as "iphelpers".
Don
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This helps the community, keeps the forums tidy, and recognises useful contributions. Thanks!)

Macbook Pro 2.2 ghz and HD movie import/ export

I have a Canon HG 10 high definition video camcorder. I have been reading about its avchd compression and how the compressed data from the camcorder gets expanded and converted to Apple Intermediate Codek before Imovie 08 may perform any edits; and then Imovie must export or "share" the movie thru quicktime before it can be used by hardware or applications like IDVD.
Apparently I can maintain the 1920 X 1080 format thru the entire process if I save as a quicktime movie and view the movie on an external HD monitor connected to my computer.
However I've read in discussions that my macbook pro 2.2 ghz may not be sufficient for retaining the full quality of an HD movie-- Imovie itself warns me that the movie quality may be degraded unless I import at 960 X 540-- that may not be a bad idea-- I might not even notice a difference and I'd consume far less disk space-- but I would like to have the option of the highest quality video if possible. After all, I thought my camera was compatible with Imovie (as listed by Apple on its website).
Could someone explain exactly how my macbook pro may degrade my HD import more than, say, a Mac Pro would? Would it help to upgrade to 7200 rpm hard drive and 4gb ram? Thanks!

kjersti.onitemi,
My apologies for the broken links in that article. I have reported them to the appropriate group for their action.
At this point, you may find more information by using another one of Apple's support resources - https://getsupport.apple.com/GetproductgroupList.action.
Jeff D.

DHCP SCOPE Option 67 string value for OS deployment

I am completely new to OS Deployment and very less knowledge on dhcp. We are using SCCM2012 in our environment. I am confused on what should be the string value for DHCP 67 OPTION . Does the \ back slash make any
difference when setting a string value. for example- \\smsboot\x64\wdsnbp.com or \smsboot\x64\wdsnbp.com or would i need to specify the complete path where remote install folder is located for example \\server name\c$\remoteinsall\smsboot\x64\wdsnbp.com
.I cant test myself due to restrictions in our organization as the DHCP servers are handled by other team . Appreciate your help!!!

Hi,
>>what should be the string value for DHCP 67 OPTION
The Option 67 should be SMSBoot\x86\wdsnbp.com
Best Regards,
Joyce
We
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Thanks for helping make community forums a great place.

2 database EE and XE..import export

i have 2 DB installed on my PC..
1) Oracle Database 10g Release 10.2.0.1.0 - Production and
2) Oracle Database 10g Express Edition
i am trying to IMPort a schema (002n) from EE into XE by the name (002)
i have created the schema "002" in XE.
but when issue IMP command from the command. i think it is running the IMP
utility of the EE file location...
in the Environment variable of XP,,the path is ;
C:\oracle\product\10.2.0\db_1\bin;
C:\oraclexe\app\oracle\product\10.2.0\server\bin;
i get the foollwing error;
D:\002>imp file=002_290511.dmp fromuser=002n touser=002 userid=002/002@xe
Import: Release 10.2.0.1.0 - Production on Mon May 30 18:54:15 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
IMP-00058: ORACLE error 12154 encountered
ORA-12154: TNS:could not resolve the connect identifier specified
IMP-00000: Import terminated unsuccessfully
i tried even to import from EXpress Edtion utiliy from the browser
via..Home>SQL>SQL Scripts>Import Script
there it says ;
Not compatible
Your export file is not supported.
Please if some one guide how do i successfully do this IMPort.

Thanks Mr. Lubiez & sb92075
here is the setting for you refernce;
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\RSH>D:
D:\>CD 002
D:\002>SET
ALLUSERSPROFILE=C:\Documents and Settings\All Users
APPDATA=C:\Documents and Settings\RSH\Application Data
CLIENTNAME=Console
CommonProgramFiles=C:\Program Files\Common Files
COMPUTERNAME=RSHD
ComSpec=C:\WINDOWS\system32\cmd.exe
FP_NO_HOST_CHECK=NO
HOMEDRIVE=C:
HOMEPATH=\Documents and Settings\RSH
LOGONSERVER=\\RSHD
NUMBER_OF_PROCESSORS=2
OS=Windows_NT
Path=C:\oraclexe\app\oracle\product\10.2.0\server\bin;C:\oracle\product\10.2.0\d
b_1\bin;C:\orant\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\
orant\jdk\bin
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH
PERL5LIB=C:\oracle\product\10.2.0\db_1\perl\5.8.3\lib\MSWin32-x86;C:\oracle\prod
uct\10.2.0\db_1\perl\5.8.3\lib;C:\oracle\product\10.2.0\db_1\perl\5.8.3\lib\MSWi
n32-x86;C:\oracle\product\10.2.0\db_1\perl\site\5.8.3;C:\oracle\product\10.2.0\d
b_1\perl\site\5.8.3\lib;C:\oracle\product\10.2.0\db_1\sysman\admin\scripts;
PROCESSOR_ARCHITECTURE=x86
PROCESSOR_IDENTIFIER=x86 Family 6 Model 15 Stepping 13, GenuineIntel
PROCESSOR_LEVEL=6
PROCESSOR_REVISION=0f0d
ProgramFiles=C:\Program Files
PROMPT=$P$G
SESSIONNAME=Console
SystemDrive=C:
SystemRoot=C:\WINDOWS
TEMP=C:\DOCUME~1\RSH\LOCALS~1\Temp
TMP=C:\DOCUME~1\RSH\LOCALS~1\Temp
USERDOMAIN=RSHD
USERNAME=RSH
USERPROFILE=C:\Documents and Settings\RSH
windir=C:\WINDOWS
D:\002>PATH
PATH=C:\oraclexe\app\oracle\product\10.2.0\server\bin;C:\oracle\product\10.2.0\d
b_1\bin;C:\orant\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\
orant\jdk\bin
D:\002>LSNRCTL STATUS
LSNRCTL for 32-bit Windows: Version 10.2.0.1.0 - Production on 30-MAY-2011 21:31
:12
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC_FOR_XE)))
STATUS of the LISTENER
Alias                     LISTENER
Version                   TNSLSNR for 32-bit Windows: Version 10.2.0.1.0 - Produ
ction
Start Date                30-MAY-2011 18:11:35
Uptime                    0 days 3 hr. 19 min. 36 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Default Service           XE
Listener Parameter File   C:\oraclexe\app\oracle\product\10.2.0\server\network\a
dmin\listener.ora
Listener Log File         C:\oraclexe\app\oracle\product\10.2.0\server\network\l
og\listener.log
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC_FOR_XEipc)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=rshd)(PORT=1522)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=8080))(Presentation=
HTTP)(Session=RAW))
Services Summary...
Service "CLRExtProc" has 1 instance(s).
Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "XEXDB" has 1 instance(s).
Instance "xe", status READY, has 1 handler(s) for this service...
Service "XE_XPT" has 1 instance(s).
Instance "xe", status READY, has 1 handler(s) for this service...
Service "xe" has 1 instance(s).
Instance "xe", status READY, has 1 handler(s) for this service...
The command completed successfully
D:\002>LSNRCTL SERVICE
LSNRCTL for 32-bit Windows: Version 10.2.0.1.0 - Production on 30-MAY-2011 21:19
:26
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC_FOR_XE)))
Services Summary...
Service "CLRExtProc" has 1 instance(s).
Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0
         LOCAL SERVER
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0
         LOCAL SERVER
Service "XEXDB" has 1 instance(s).
Instance "xe", status READY, has 1 handler(s) for this service...
    Handler(s):
      "D000" established:107 refused:0 current:27 max:1002 state:ready
         DISPATCHER <machine: RSHD, pid: 2992>
         (ADDRESS=(PROTOCOL=tcp)(HOST=RSHD)(PORT=1031))
Service "XE_XPT" has 1 instance(s).
Instance "xe", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
Service "xe" has 1 instance(s).
Instance "xe", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
The command completed successfully
D:\002>
Is XE well defined in the tnsnames.ora ?
XE =
(DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = rshd)(PORT = 1522))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
ORACLR_CONNECTION_DATA =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
    (CONNECT_DATA =
      (SID = CLRExtProc)
      (PRESENTATION = RO)
Did you use DATAPUMP to export ( expdp )?No. i used EXP

Best Practices - How to adjust light in selected areas and best options for export (only adjust ligh

Hello,
I have the cs suite, and recently downloaded the lightroom demo. I am fairly good with picking up programs but couldn't locate where or how i can select individual elements to lighten/darken? If i wanted to make a an object lighter, should i be doing this within ps or is there an easy to use tool within lightroom?
Second question, when exporting into ps, what is the best practice.. should i only adjust lighting and any other edits within ps?
cheers
Kenny from Vancouver

Kenny
Take a look at the Adjustment Brush. It's in the tool pallette, just below the histogram when you're in the Develop Module. It will not only dodge and burn, but allow you to apply lots of other kinds of local changes.
In general, I find that I can do everything in Lightroom for most images.
Hal

Improving Oracle9i DB performance using IMPORT/EXPORT

Hi,
I'm experiencing wrong performance on Oracle9.2.0.6 DB for production system.
I have one schema and two tablespaces: the first one for data (18 datafiles sized each 1GB), and the second one for indexes (15 datafiles sized each 1GB).
I tryed to tune the db using statpack and noticed "Waits due to Row being locked by an active Transaction".i couldn't do very much for solving this issue.
So, I'm wandering if using import/export utility against database would be a solution to obtain better performance. I can follow two methods for I/E:
FIRST METHOD:
1. Take a good export (with COMPRESS=n).
2. drop the tablesapces.
3. recreate the same tablespaces (data and index).
4. make data as default and revoke RESOURCE role from user.
5. grant quota unlimited on DATA TABLESPACE and INDEX tablespace to the user.
6. Just import (single import would do). imp user/pass fromuser=x touser=y indexes=y constraints=y.
Now since both data/index tablespaces already exist, the indexes will be created in their intended tablespaces.
SECOND METHOD
Instead of Imp or exp I can use move tablespace cmd to avoid fragmenation.
1.create new tbs.
2.move all objects to new tbs.
- rebuild all indexes to new tbs.
3.drop old tbs.
4.rename new tbs name to old tbs names.
Please, could you suggest If I'm following the right way to achieve better performance?
Thanks in advance.
Claudia

"Waits due to Row being locked by an active Transaction" is an indicator that you have a blocking problem, not fragmentation. Do you have long transactions? In Oracle, only writers block writers so it appears you have multiple sessions trying to modify the same row(s).
And, on the import/export - What type of disk is attached to the system? If it is a SAN it is likely that you already have a decent degree of data distribution between data and indexes.

DHCP Server does not work after Exporting and Importing Using Netsh Command

Hello Friends :
I had two dhcp servers in windows server 2003 server , I have upgraded one of them to windows server 2008 32 bit and again i installed a windows server 2008 R2 as an additional Domain Controller , the last scenario was like this :
srv-1 : windows server 2003 + DHCP = working with no problem
srv-2 : windows server 2003 + DC + DHCP = Worked without problem
srv-3 : windows server 2008 R2 + DC = worked without any problems
I exported the DHCP server configuration on the srv-2 using netsh dhcp server export and Imported them to srv-3 using the
netsh dhcp server import command , the command completed successfully and i can see all of the scopes without any problems and errors , i have authorized the new server without any problem , all scopes are activated without any problem so i
disabled the srv-2 DHCP service and unauthorized it from active directory , the problem is that the new server semms that does not lease any address to clients !!!
1- I have authorized it
2- I used Rogue Checker tool in client computers they see authorized server without any problems
3- The same tool in workgroup only shows srv-1 as the DHCP server and does not see other DHCP servers
4- Bindings are OK and DHCP servers only have one NIC installed on them
What can i do to make sure my srv-3 DHCP server will work on the network ?
thanks ...
MIMO

Are the clients on another network so you need to configure a DHCP relay agent?
If you load up perfmon on the dhcp server and remove all counters and then add DHCP counters. Do you see any dhcprequests when you reboot your dhcp clients? This will determine if your server actually receives any dhcp requests.
Have you check event viewer for any warnings or errors?
And the classic one restarted the dhcp server service (or reboot)?
Regards Per-Torben Sørensen http://pertorben.wordpress.com/

How can configure scope options in dhcp server

Good Night Partners.
I need configure scope options in dhcp server on mac mini.
i dont know how to do.
its my first mac and i confuse.
Can anybody help me please.

Are you referring to DHCP Option Codes? If so then this can be done with the DHCP server included with Mac OS X Server. However Apple do not provide a tool for doing this nor for encoding the values in the required format.
What you will need to do is edit the DHCP Server configuration file manually using a text editor. This configuration file is located at /etc/bootpd.plist before you do this I advise having a read of the Unix man page for bootpd (the DHCP server software Apple use).
You can use a utility I have written to generate the required information and then paste this in to /etc/bootpd.plist it can be downloaded from -
http://web.me.com/jelockwood/MyUtilities/dhcp.html

Firefox freezes trying to download or save files, Import/Export bookmarks, clicking (Tools) Options (was: Fire Fox crashes in Windows safe mode and in Firefox Safe mode)

Hi
XP sp3 4gb ram
Firefox 6.0.2
Firefox crashes every time I do any of the following. Then I have to force quit Fire fox.
If i click a download link on a web page, Firefox freezes the instant I click the link
...but Firefox does not freeze if I click a web link on a web page or page navigation link.
If i go to the Menu bar > Tools > Options, Firefox freezes the instant I select Options from the Tools menu.
...but Firefox does not freeze if select any other item from the Tools menu.
If I go to the Menu bar > File, Firefox instantly freezes the instant I select either "Save Page as..." or "Open file..."
...but Firefox does not freeze if I select any other option from the File menu such as: New Tab, New Window, Send Link, page Setup, Print, Exit etc
If I go the Menu Bar > Bookmarks > Show all Bookmarks > Import and Backup, Firefox instantly freezes the second I select "Import" or "Export"
... but Firefox does not freeze if I select any other command in the Bookmarks sub menus, nor does it freeze if I back out of the menu entirely.
Same as above for History if I select "Import" or "Export"
...so I have isolated the problem to a limited number of commands in Firefox that cause Firefox to freeze... described above. Everything else in Firefox works fine.
HERE IS A SUMMARY OF WHAT CAUSES THE FREEZING:
• Clicking a download link on a webpage
• Going to the Menu Bar > File and selecting "save as" or "Open File"
• Going to the Menu bar > Tools and selecting Options.
• Going to Bookmarks > Show all Bookmarks > Import and Backup and selecting either "Import" or "Export"
• Same as above for History if I select "Import" or "Export"
Everything else in Firefox works fine. I went through every menu command and checked for freezes. Only the commands I mentioned above cause the freezing.
I tried the following to try to fix it:
• Reset my modem and router (Problem still exists)
• Uninstalled FF. Deleted folders, profiles (Downloads.sqlite), Registry entries. Reinstalled. (Problem still exists)
• Restarted FF in Firefox safe mode. (Problem still exists)
• Restarted in Windows Safe mode and then started FF in Firefox safe mode (Problem still exists)
• Disabled Window firewall. Disabled ZoneAlarm firewall, Shutdown ZoneAlarm firewall. Set Internel Options to default settings. (Problem still exists)
• I reset the config option: browser.download.manager.scanWhenDone to false
What does work?
• Firefox does not crash when I click a link an go a website, navigate a page, use a menu item command.
• Firefox works fine on my other computer.
• Internet Explorer works fine on the computer that Firefox is having a problem on.
• My other applications work fine on the computer that Firefox is having a problem on.
I want to add that, I just overcame the XP Recovery Virus by following a post that suggested running the following software to fix the virus. Everything seems back to normal except Firefox.
The software I ran to fix the problem are listed below:
• malwarebytes
• superantispyware
• ccleaner
• combofix.
• smart defrag
• then load a good anti-virus. (I ran Zone Alarm virus scan)

Hi.
This is about a question you posted to the Firefox Support forum three months ago (I'm sorry you never got an answer).
Did you ever fix the problem where Firefox freezes or hangs, when clicking a download link or using (File menu) "save as" or "open file"? Or when going to the Firefox (Tools) menu and clicking Options ? Or trying to Import or Export bookmarks?
I found this thread searching for a solution for someone on MozillaZine's support forum who's having a similar issue. See this thread: (maybe something he's tried that didn't work for him will work for you?)
http://forums.mozillazine.org/viewtopic.php?f=38&t=2382953&start=15
<br>Cannot download or click tools -> options

Ip source guard feature and dhcp DHCP scope exhaustion (client spoofs other clients)

Hi everybody.
A dhcp server assigns ip adress based on mac address carried by client hardware field in dhcp packets.
One potential attack is when a rogue host mimics different mac addresses and causes dhcp server to assign the ip addresses until no ip address is left for legitimate host.
For e.g a host h1 with mac1 has assigned ip address by dhcp server as:
199.199.199.1 mac1
Dhcp server has the above entry in its database.
Using hacking tools such as Yersinia or Gobbler one can create a dhcp discover messages each time creating a different mac for client hardware field in dhcp server thereby causing a dhcp server to assign ip addresses because to dhcp server , these are legitimate dhcp discover messages with each carrying a different mac in client hardware addresses.
You might say use dhcp snooping and it will prevent that ( dhcp scope exhaustion) and configure the switch to check if src mac matches the client hardware address in dhcp message. But still we can creat spoofed discover messages where src mac in ethernet header will match the client hardware address in dhcp discover message. We still did not overcome the problem.
You might say use IP source guard feature but will it really prevent that problem from happening?
Let me illustrate it :
h1---------f1/1SW---------DHCP server
Let say we have configured dhcp snooping on sw1 and f1/1 is untrusted port. The switch has following dhcp binding
199.199.199.1    mac1   vlan1 f1/1
Next we configure ip source guard to validate both src mac and src ip against the dhcp bindings . When we configures ip source guard first , it will allow dhcp communication only so a host can request ip address and a dhcp binding can be built. After that ip source guard will validate src ip or src mac or both against the dhcp binding.depending upon how we configure ip source guard.
In our case we have configured ip source guard to validate both src mac and src ip against the dhcp binding.
A dhcp binding is already created as:
199.199.199.1 mac1 vlan 1 f1/1
Now using the hacking tools Yersinia or Gobbler on h1, we create our first spoofed dhcp discover message where src mac=mac2 in ethernet header and client harware address= mac2 in dhcp discover message. Since switch is configured with ip source guard feature and therefore allows dhcp discover message to pass through. Dhcp server upon receiving the dhcp message assigns another ip address from the pool. Now the dhcp server has following entries:
199.199.199.1 mac1
199.199.199.2 mac2.
We can continue to craft spoofed dhcp discover messages as mentioned above and have dhcp server keep assigning ip addresses until the whole pool is exhausted.
So my question is how does ip source guard in conjuction with dhcp snooping prevent this particular attack from happening? ( i.e DHCP scope exhaustion)
I really appreciate your input.
thanks and have a great week.

Thanks Karthikeyan.
First of all, we gather all the information about the locations of legitimate dhcp servers in our network. Once we have this information, we will configure the ports used to reach them as trusted. All the ports where end users will connect will be untrusted and therefore subject to dhcp snooping .
it means if any of user connected in that switch/vlan runs a dhcp services like vmware for eg. Snooping will prevent the dhcp/bootp servers connected to that port will not be able to process.
Yes that is correct. Because dhcp snooping feature will check these ports for the messages usually sent by dhcp server such as dhcp offer, etc. If the end user is running dhcp server using virtual machine, that port should be configured as trusted if it is dertermined that end user is running a legitimate dhcp server using vm ware.
When we have the dhcp snooping it prevents the 1st level of hacking itself. I don't think so it will have any impact on dhcp address releasing.
I am sorry. You lost me here. What is 1 level of hacking?
Dhcp snooping checks for dhcp messages such as dhcp release, dhcp decline.on untrusted port against the dhcp bindings.
Here is why;
h1---------SW1-------dhcp server
               |
             h2
Let say we don't have dhcp snooping in above attack and h2 is a legitimate user has already assigned ip address 199.199.199.2 by dhcp server. Thus the dhcp server has an entry:
199.199.199.2 mac2
Next we connect rogue user and it gets ip address 199.199.199.1 now the dhcp server has entries:
199.199.199. 1 mac1
199.199.199.2   mac2
Now using hacking tools, h1 create a fake dhcp release message with 199.199.199.199.2   mac2
Dhcp server upon receiving this message, will release the ip address and returns it to the pool.
By using DHCP snooping, switch will peer inside dhcp release message and checks against the binding. If there is conflict, it will drop the message.
IFor e.g
If have dhcp snooping configured , then switch will have adhcp binding as:
199.199.199.1    mac1    vlan 1   f1/1 lease time
199.199.199.2     mac2    vlan 2    f1/2 lease time.
If h1 tries to send fake dhcp release with ip address 199.199.199.2    mac2
Switch will check ip address 199.199.199.2 and mac2 against the binding related to f1/1 . Sw will find a conflict and therefore drops the dhcp release packet.
Thanks

Client Authentication/Authorization via ISE & AD, Posture Registry Key, and mapped to specific DHCP scope by AD membership

Hi Team,
I'm currently working on a configuration entailing WLC and ISE where the customer wants a single SSID,and wants his wireless clients to authenticate successfully if they pass a registry key compliance. Additionally, they want clients to received a different IP address or get mapped to a different DHCP scope based on the Microsoft AD group they belong too. for example:
Client authenticating with registry key and in AD group ABC that passes authentication gets IP address or subnet for AD group ABC.
Client authenticating with registry key and in AD group XXX that passes authentication gets IP address or subnet for AD group XXX.
Clients---->WLC------>ISE-----> MS AD ( groups ABC, XXXX, YYY )
currently using EAP-PEAP/MSCHAPv2
Does anyone have any idea or pointers or can refer me somewhere that I can read on how to accomplish this? Not sure on how to do the registry compliance check nor what attributes will allow me to map the client to a DHCP Scope based on this AD group membership?
Thanks...

Do check cisco how to guides you will get step by step configuration of the current requirement

Getting "Error in setting DHCP Scope Network and Netmask"

Hello Cisco Experts - I'm trying to setup a new DHCP scope on my Cisco 2504 and am getting the error referenced above. Here are the settings I am using:
I have another range setup in exactly the same way only it runs from 10.35.209.65 through 10.35.209.90. Can anyone point me in the right direction for what I'm doing wrong? Thanks in advance!

Good question.
Here is the screeshot of the scope I just activated:
What IOS Version are you running? I have 7.4.100.0 on mine.
Please Rate Helpful posts and mark this question as answered if, in fact, this does answer your question. Otherwise, feel free to post follow-up questions.
Charles Moreton

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