Archive for the ‘DHCP’ Category

Active Directory

1) Review User Accounts and remove retired accounts.

2) Run Microsoft’s Domain Controller Diagnostics – From a command prompt, run dcdiag.exe (on DC only). If the commands are unrecognized, install Windows Support Tools.

3) Verify that approved password policy is being enforced.

4) Review the domain controller disk space reports.

5) Check your backups – AD backup includes capturing system state, information related to AD database, logs, registry, boot files, SYSVOL and other system files.

6) Check to make sure that AD replication is working correctly. To check, you can run the following command:
repadmin /showrepl

7) Check event logs for persistent errors.

8) Perform defragmentation to increase performance as large directories running for long time can get large and fragmented.

9) Verify integrity of AD DS database files with respect to AD semantics using NTDSUTIL.

DNS

1) Review DNS Records for obsolete static entries.

2) Ensure DNS Scavenging is configured.

3) Clean up forwarders

4) Remove stale zones

5) Remove WINS dependencies (DNS is fully capable of providing all long and short name resolution services)

6) Security Aspects
– Allow only secure dynamic updates for all DNS zones. This ensures that only authenticated users can submit DNS updates using a secure method, which helps prevent the IP addresses of trusted hosts from being hijacked by an attacker.
– If the server running the DNS Server service is a domain controller, use AD ACLs to secure access control of the DNS Server service.

DHCP

1) As always, check logs for critical DHCP related events. It would be recommended to implement a proactive monitoring solution for real-time data.

2) Frequent maintenance of the DHCP database is needed to keep it functioning properly and to recover whitespace. While DHCP is configured to do online maintenance to the database by default when there are no client requests; for busy DHCP servers, which possibly doesn’t have downtime, it is recommended to run offline maintenance against the dhcp.mdb file on a quarterly or half-yearly basis.
On a DHCP server computer, open a command prompt (Administrative access)
Use the Jetpack.exe tool to perform offline compaction.
Syntax: jetpack database_name temporary_database_name

Example:
cd WINDOWS\system32\dhcp
net stop dhcpserver
jetpack dhcp.mdb tmp.mdb
net start dhcpserver

This should work for both Windows Server 2003 and Windows Server 2008

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This article explains the steps taken to export DHCP scopes from one server and import them to another or from old to new server. I have tried and tested them for DHCP on Windows Server 2003.

Run the following from command prompt using administrator login. You can try running this from any domain computer.

C:\> netsh dhcp server \\dhcpservername1 export C:\DHCPServerScope1 all

This exports the DHCP scope from this server to a file called “DHCPServerScope1” under C drive.

If the above method does not work due to invalid path error, which is possible; then you can export the scopes by logging into the DHCP server. You can then export and save the scopes to the local or shared folder. After this, to import the scopes, you can log into the other DHCP server and again using “netsh.exe” utility import the configurations of the scopes to the other DHCP server (Recommended)

To export scopes following syntax can be used:

netsh dhcp server export <Filename> <ScopeList>

Example:

C:\>netsh dhcp server export c:\scopes\DHCPServerScope1 10.0.0.1

To import scopes following syntax can be used:

netsh dhcp server import <Filename> all

Example:

C:\>netsh dhcp server import c:\scopes\DHCPServerScope1 all