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DHCP Runtime

  • Article

Applies To: Windows Server 2008

Dynamic Host Configuration Protocol (DHCP) runtime includes normal operating functions of the DHCP server. Examples of these functions include lease issuance and rogue detection.

Aspects

The following is a list of all aspects that are part of this managed entity:

Name Description

DHCP Audit Logging

Dynamic Host Configuration Protocol (DHCP) servers include several logging features and server parameters that provide enhanced auditing capabilities. You can specify the following features:

  • The file path in which the DHCP server stores audit log files. DHCP audit logs are located by default at %windir%\System32\Dhcp.
  • A maximum size restriction (in megabytes) for the total amount of disk space available for all audit log files created and stored by the DHCP service.
  • An interval for disk checking that is used to determine how many times the DHCP server writes audit log events to the log file before checking for available disk space on the server.
  • A minimum size requirement (in megabytes) for server disk space that is used during disk checking to determine if sufficient space exists for the server to continue audit logging.

DHCP Authorization and Conflicts

When configured correctly and authorized for use on a network, Dynamic Host Configuration Protocol (DHCP) servers provide a useful administrative service. However, a misconfigured or unauthorized DHCP server can cause problems. For example, if an unauthorized DHCP server starts, it might begin either leasing incorrect IP addresses to clients or negatively acknowledging DHCP clients that attempt to renew current IP address leases.

To resolve these issues, DHCP servers are verified as authorized in Active Directory Domain Services before they can service clients. This prevents most of the accidental damage caused by either misconfigured DHCP servers or correctly configured DHCP servers running on the wrong network.

DHCP Backup/Restore

Maintaining a backup of the Dynamic Host Configuration Protocol (DHCP) database protects you from data loss in the event of data corruption or a hard disk failure.

 There are three backup methods supported by the DHCP Server service:

  • Synchronous backups that occur automatically. The default backup interval is 60 minutes.
  • Asynchronous (manual) backups, performed by using the Backup command in the DHCP snap-in.
  • Backups using Windows Backup (Ntbackup.exe) or other backup software.

When a synchronous or asynchronous backup occurs, the entire DHCP database is saved.

DHCP BOOTP Boot File Configuration

The Bootstrap Protocol (BOOTP) is a host configuration protocol developed before Dynamic Host Configuration Protocol (DHCP). DHCP improves on BOOTP and resolves its limitations as a host configuration service.

To configure your DHCP server to assign Internet Protocol (IP) address information to BOOTP clients, you must add a reservation for each BOOTP client. The reservation builds an association between the media access control (MAC)  address and the IP address.

DHCP General Availability

General availability of the Dynamic Host Configuration Protocol (DHCP) server refers to its ability to service clients. General availability depends on:

  • Proper authorization of the DHCP server
  • Presence of Active Directory Domain Services
  • Successful loading of the DHCP dynamic-link libraries (DLLs)

DHCP Lease Issuance

Internet Protocol (IP) addresses are leased by the Dynamic Host Configuration Protocol (DHCP) server to its clients. Each lease has an expiration date, which the client must renew if it is going to continue to use that IP address. If conflict detection is enabled, the DHCP server pings the client before assigning the IP address to determine whether an IP address is already in use on the network.

If the DHCP client cannot be pinged by the server, the server assumes no IP address conflict and assigns the IP address to the client.

DHCP Server Active Directory Availability

For proper authorization and operation, the Dynamic Host Configuration Protocol (DHCP) server relies on a valid Active Directory Domain Services configuration. The DHCP server must find a valid directory services-enabled domain controller.

DHCP Server Communication

For proper network communication between the Dynamic Host Configuration Protocol (DHCP) server and other network services, such as Active Directory Domain Services and Winsock, the DHCP server must have a working network connection.

DHCP Server DNS Registration

You can configure the Dynamic Host Configuration Protocol (DHCP) Server service to impersonate an account to perform Domain Name service (DNS) registrations and secure dynamic updates. The Netsh.exe tool can be used to configure the impersonation credentials. You must create a dedicated user account in Active Directory Domain Services before you use the Netsh.exe tool to configure the use of impersonation credentials.

DHCP Server Interface Change Notification

When the network interfaces or Internet Protocol (IP) addresses with which the Dynamic Host Configuration Protocol (DHCP) server is configured are changed, the server might not recognize these changes, and the interfaces might not function correctly.

DHCP Server Rogue Detection

When configured correctly and authorized for use on a network, Dynamic Host Configuration Protocol (DHCP) servers provide a useful administrative service. However, a misconfigured or unauthorized DHCP server can cause problems. For example, if an unauthorized DHCP server starts, it might begin either leasing incorrect IP addresses to clients or negatively acknowledging DHCP clients that attempt to renew current address leases.

To resolve these issues, DHCP servers are verified as authorized in Active Directory Domain Services before they can service clients and unauthorized, or rogue, servers are detected. This prevents most of the accidental damage caused by either misconfigured DHCP servers or correctly configured DHCP servers running on the wrong network.

DHCP Service Initialization

When the Dynamic Host Configuration Protocol (DHCP) Server service initializes, it checks for proper configuration of Transmission Control Protocol/Internet Protocol (TCP/IP), including the presence of a static IP address. Successful initialization results when the DHCP server has established network communication by using TCP/IP.

DHCP Users Group Configuration

To function properly, the Dynamic Host Configuration Protocol (DHCP) service must be able to create or look up the DHCP Users and DHCP Administrators local groups.

DHCP Infrastructure