We have about 20 sites with DHCP servers. So, this is a significant number of servers and scopes to manage. The Microsoft DHCP management console can be sluggish across a WAN so managing each server through RDP can be a pain also. Fortunately, the netsh dhcp server command set gives a good set of tools for managing DHCP services through a command line.

The netsh dhcp server help says:

Switches the active command context to the specified DHCP server.

Syntax:
dhcp> server <\\ServerName | ServerIP>

Parameters:
ServerName     – The NetBIOS or the DNS name of the DHCP server computer.
ServerIP       – The IP address of the DHCP server computer.

Notes:         If a value for neither ServerName nor ServerIP is specified, the local computer is assumed.

Examples:      server \\DHCP-SRV1
server \\dhcp-srv.microsoft.com
server 10.0.0.1

Using this command and the additional options available to manage DHCP, I wrote a script to go out to each DHCP server, make a copy of all scopes on that server and write it to a central location. The script is shown below. A prerequisite to the script is to get a copy of the psexec.exe tool from Sysinternals (Microsoft). I could use the remote server format of the command but prefer running the command on the remote servers’ command line.

The backup script is shown below. I named mine PS-dhcp-export.cmd

The first part of the script writes a batch file unique to each remote server.

:part1

if exist get-dhcp.cmd del get-dhcp.cmd
echo net use j: /d > get-dhcp.cmd
echo net use j: \\backupserver\c$ >> get-dhcp.cmd
echo j: >> get-dhcp.cmd
echo cd “\dhcpbackup” >> get-dhcp.cmd
echo netsh dhcp server export j:%1.txt all >> get-dhcp.cmd

Part2 actually runs the script on the remote computer and copies the get-dhcp.cmd file to the remote computer’s C:\ folder.

:part2
psexec -c -w c:\ get-dhcp.cmd \\%1

So, to run this against all remote site’s dhcp servers, I create a text file listing each remote authorized DHCP server. There is one server per line and looks something like this:

us1dc01
th6dc01
us2dc01
mx1dc01
us9dc01
us7dc02
uk3dc01
tw3dc01
us4dc01

This file is then read in and processed using the following backupdhcp.bat file:

for /F “tokens=*” %%I in (sites.txt) do call ps-dhcp-export.cmd %%I

Wait a few minutes and the backup is completed across all DHCP servers and a copy of the scopes is in one folder on another server.

If a scope needs restored or installed on a new DHCP server, use a command similar to the following:

netsh dhcp server import backupfile.txt scopesubnet

Where scopesubnet is either “ALL” or the subnet range like 10.2.0.0 or similar. More help can be found on the Microsoft Technet website for the netsh commands for DHCP.

Hope this tip has been useful. Thanks for reading & let’s continue to be good network citizens!

I wanted to bring your attention to a recent posting on the excellent SANS organization website about the pandemic watch of 2009. This posting is titled Pandemic Watch April 2009. This has very good explanations of the current situation and the potential health risks.

The section that I think is most appropriate to IT folks (actually to everyone) describes a skeleton plan for companies to help deal with the situation. The following is an excerpt from the SANS website.

Don’t Panic!

Initial monitoring stage (where we are right now)

* If you’re sick, stay home
* Family is sick, stay home
* Close contact with someone showing symptoms, stay home
* Wash your hands, cover your cough

Then, if multiple cases in your area,

* Think about telling non-essential workers to stay home
* Recommend workers take kids out of daycare

Pandemic stage

* Everyone will be staying home, how will you handle it?
* Do you have enough laptops?
* Can your VPN concentrators handle the load

I would recommend taking some time to read the summary about the health risks of the various flu strains. Let’s continue to keep our thoughts and best wishes for those who have already been affected by this most recent health issue.

Thanks for reading and let’s continue to be good network citizens – stay healthy too and if you are not healthy, then please contact a health care organization as soon as you can. Get well soon!

One group I participate in is a mailing list from SANS. If you have not attended a SANS event or education, then you should try to get to one of their events. They are one, if not, the premier non-vendor related security and systems administration group in the IT industry. I posed the same question to this peer group and have had some very good responses. Some suggestions for solutions have come back and include:

Microsoft Office SharePoint (http://www.microsoft.com/sharepoint/default.mspx)

OpenText – Livelink (http://www.opentext.com/2/sol-products/sol-pro-llecm10.htm)

Webex Connect – (http://webex.com/enterprise/index.html) (There are other flavors for small & medium business)

 Accellion – (http://www.accellion.com)

These are very interesting solutions and I will certainly be looking at all potential candidates. One thing that bothers me about the SharePoint option is its security capabilities. SharePoint is typically Microsoft Active Directory integrated. This has major security implications and in fact CSO magazine has posted a recent article on this topic. I recommend that you read the article and understand what risks the SharePoint solution may open for your organization.

Why Security Pros Hate Microsoft SharePoint

Microsoft’s SharePoint collaboration platform is all the rage in today’s business world, especially since third parties gained the ability to plug security holes. But managing it can still be a nightmare for IT security shops.

I am still looking for more references and ideas for this solution, so please share what you are doing for your organization and it will be much appreciated by me and other readers.

Check out the TCP/IP tutorial. It’s a quick easy read that you can share with those you are trying to explain how a network works.

Checkout this website. I guarantee that if networks are in your blood, you will find something of interest here.

Thanks for your time. Let’s be good network citizens together & practice safe networking!

Thanks for your time. Let’s be good network citizens together & practice safe networking!