DHCP paper

DHCP paper

A Dynamic Host Configuration Protocol or DHCP refers to a client/server protocol that automatically gives an IP host the IP address and other configuration information such as the default gateway and the subnet mask.

Building a DHCP server

Activity

When building a set of rules must be followed, this refers to the protocol element of the name. At this point the hosts/clients intend to join the network. The host initiates by requesting a DHCP server. The server relates an address to the host.

When a computer joins a network it cannot tell whether a DHCP server is available, it can only broadcast a signal to the whole network enquiring whether if one is available, the server will reply by giving an IP address, the host then responds by officially requesting for an address. The DHCP gives the address to the host with a lease time of a limited period (take 12hours for this case).

In terminating the host gives returns the address to the DHCP. The address is can now be issued to other computers within the network, at times the address is not received to the server side, in such a case the server retrieves the address after the lease time lapses since it cannot issue the same address twice.

In order for the DHCP server to lease IP addresses it must first be activated. Before activating a new scope, you should have the specified DHCP options for it.

Authorizing the DHCP Server in Active Directory

Authorization is required while integrating DHCP servers into Active Directory networks. Only domain member and controller’s servers participate in Active directory, only these servers can be Authorized.

When an Active Directory is included in the network, the first DHCP server to be installed has to be an authorized server. Before the DHCP server which is a member of an Active Directory is allowed to issue IP addresses to the client within a network, it has to be authorized to achieve this. It stops a DHCP server with incorrect information from being introduced to the network.

Steps for Authorizing the DHCP server.

1. Right click on server and select Authorize
2. Refresh on the dialog box until the DHCP server appears.
3. Check on the status panel to check whether the DHCP is configured and ready to lease IP.
4. To unauthorized, click on the DHCP server and select unauthorized.

Management of DHCP Databases

The DHCP dynamic database is updated every time the clients are assigned or release the address leases.

The data base comprises DHCP configuration data that includes information relating to reservations, options, scopes and leases.

Backing up and restoring DHCP data base

If it is not possible to repair a fault in the database, it is possible to restore the database from the back up directory from the local drive if this is not possible the DHCP must be restored from an offline storage.

Guidelines in restoring a DHCP database.

1. Manually back up the DHCP database, note that the DHCP database should not be stored with the copy that was created automatically, this causes the DHCP service to malfunction.
2. Maintain a copy of the DHCP database that was backed up offline. Since the DHCP service will automatically back up a copy of the DHCP database to a location on the local drive, the user stands to lose the backup DHCP and original DHCP databases when the hardware fails.

Managing a DHCP services is necessary in reflecting the changing client IP address service, the client IP address needs change when new subnets, clients and servers are added or subtracted from the network.

Managing the DHCP services is required as a response to changing DHCP server conditions in addition to protecting the DHCP database from failure.

Reconciling feature in management.

It is possible to reconcile all features in DHCP server. One can choose whether to reconcile all scopes or a specific scope by selecting the appropriate scope. It is recommended that while logging in, a non-administrative credential and use the Run prompt using a user account.

Prior to implementing the reconcile feature to recover the client information for the DHCP scope from the register, the server computer must meet the following.

1. The DHCP server registry keys must exist, be restored and remain intact from the previous operations in the server computer.
2. A new version file of the DHCP server must be generated on the server computer.

If the criteria above is adhered to, one can then restart the service. Upon starting the DHCP console, one notices the scope information is present, however, there are no active leases displayed.

Steps for reconciling the DHCP data base

1. Select DHCP server in the console tree in the DHCP console
2. On the action menu, select the reconcile all scopes.
3. Click verify on the Reconcile all dialog box.
4. Click ok on the DHCP dialog box.

Steps to reconcile a scope in DHCP database.

1. Select the specific scope in the console tree of the DHCP console.

(one can choose to reconcile all scopes by selecting DHCP server or one scope by choosing appropriate scope)

2. Select reconcile in the action menu.
3. Click verify in the reconcile dialog box.
4. Select ok on the DHCP dialog box.

After reconciling, individual properties for individual clients shown within the list of active leases one notices the client information is not displayed correctly. This information may be corrected and updated in DHCP manager as soon as the clients renew their leases.

Monitoring and managing DHCP

Following correct configuration and use of DHCP services, one is ready to perform auditing or creating SNMP traps. Deciding on the most suitable options relies on individual implementation. It is a difficult process to manage DDNS since each subnet address range type requires a different configuration.

It is essential for the user to understand the disparity between static and dynamic address assignments. While using the static address one must use the DHCP management utility for assigning permanent IP addresses to the clients within the tree, while using the dynamic address, the DHCP server assigns the address to each client during start-up. Address may be denied to clients depending on the hardware address-based exclusion.

Events and alerts

One configures the DHCP servers so as to maintain the history of a server’s activity within the log file. Events may refer to activities considered to be of significance including, loading and unloading server problems. The events logged are dependent on parameters that are set on the server.

Events logs are saved for future references. While monitoring it is important to check the log size. Events log have a tendency to increase rapidly while conducting certain tasks.