Administering DHCP Clients
`
`After you have established the scope and defined the range of available and excluded lP
`addresses, DHCP-enabled clients can begin using the service for automatic TCP/lP
`configuration.
`
`You can use DHCP Manager to manage individual client leases, including creating and
`managing reservations for clients.
`
`Tip
`You can use the ipconfig utility to troubleshoot the IP configuration on computers that use
`DHCP, as described in Chapter 11, "Utilities Reference." You can also use ipconfig on
`TCP/IP-32 clients on Windows for Workgroups 3.11 computers and on computers running
`Microsoft Network Client version 2.0 for MS—DOS.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 107
`
`

`
`'”3ta”l"9 a.“d.,.C°“fi9”'.‘.l‘,,9 DH.C?.§E.f"9V_5AAAAA
`Administering DHCP Clients
`
`AAAAAAAAAA.................... AAAAAA............................
`
`AAAAAA
`
`...........
`
`Managing Client Leases
`
`The lease for the IP address assigned by a DHCP server has an expiration date, which the
`client must renew if it is going to continue to use that address. You can view the lease duration
`and other information for specific DHCP clients, and you can add options and change settings
`for reserved DHCP clients.
`
`F To view client lease information
`
`1.
`
`In the DHCP Servers list in the DHCP Manager window, select the scope forwhich you
`want to view or change client information.
`
`2. From the Scope menu, choose Active Leases.
`
`A¢i’isié’oi.Le’a‘§es 9 [1 1';2o1i'i;i1.u
`
`Client
`
`fié.§éW'5fi6'
`r§,11.2l]1.12.2[l1 [JimP3] -- Reservation
`
`E] Show fleservations Dnly
`
`Sort Order
`
`@ Sort leases by1P Address
`
`0 Sort leases by flame
`
`3.
`
`in the Active Leases dialog box, select the computer whose lease you want to view in the
`IP Address list, and then choose the Properties button.
`
`if you want to view only clients that use reserved IP addresses, check the Show
`Reservations Only box.
`
`4.
`
`In the Client Properties dialog box, you can view the unique identifier and other client
`information, including the lease expiration date.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 108
`
`

`
`3,
`
`E33
`
`*2;
`
`“I
`
`.2131 .0
`
`.1
`
`_l_J_nique Identifier: 2340855432
`
`Client flame:
`
`NNIEPZ
`
`139430931 5 20:53
`
`Client Qomment:
`
`Net admin machine
`
`Lease Expires:
`
`Note
`
`You can only edit the name, unique ID, and comment, or choose the Options button in the
`Client Properties dialog box for clients with reserved IP addresses.
`
`For information about the Options button in this dialog box, see "Defining Options for
`Reservations" earlier in this chapter.
`
`You can cancel the DHCP configuration information for a DHCP client that is no longer using
`an lP address or for all clients in the scope. This has the same effect as if the client's lease
`expired—the next time that client computer starts, it must enter the rebinding state and obtain
`new TCP/lP configuration information from a DHCP server.
`
`Important
`Delete only entries for clients that are no longer using the assigned DHCP configuration.
`Deleting an active client could result in duplicate IP addresses on the network, because deleted
`addresses will be assigned to new active clients.
`
`You can use ipconfig lrelease at the command prompt for a DHCP client computer to delete
`an active client entry and safely free its iP address for reuse.
`
`To cancel a client's DHCP configuration
`
`1. Make sure the client is not using the assigned IP address.
`
`2.
`
`in the IP Client list of the Active Leases dialog box, select the client you want to cancel,
`and then choose the Delete button.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 109
`
`

`
`."l.Sia'.'ri”9.5l'ld C,°"“9ll""9 DHC.P.3e."V°[§_AAAAAAAAAAAA .......
`Administering DHCP Clients
`
`LLLLLLLLLLLL
`
`..............................................
`
`............
`
`Managing Client Reservations
`
`You can reserve a specific IP address for a client. Typically, you will need to reserve addresses
`in the following cases:
`
`"
`
`'
`
`'
`'
`
`For domain controllers if the network also uses LMHOSTS files that define IP addresses
`for domain controllers
`
`For clients that use lP addresses assigned using another method for TCP/lP configuration
`
`For assignment by RAS servers to non-DHCP clients
`For DNS servers
`
`If multiple DHCP servers are distributing addresses in the same scope, the client reservations
`on each DHCP server should be identical. Otherwise, the DHCP reserved client will receive
`different IP addresses, depending on the responding server.
`
`important
`The IP address and static name specified in WINS take precedence over the IP address
`assigned by the DHCP server. For such clients, create client reservations with the IP address
`that is defined in the WINS database.
`
`’’ To add a reservation for a client
`
`1. From the Scope menu, choose Add Reservations.
`
`l_P Address:
`
`11 105.41 .25
`
`Ll_nique Identifier: U8UU2b2b33U8
`
`Client flame:
`
`HIKEHAS1
`
`Client Qommentz
`
`2.
`
`In the Add Reserved Clients dialog box, type information to identify the first reserved client:
`
`"
`
`IP Address specifies an address from the reserved address pool. You can specify any
`reserved, unused IP address. DHCP Manager checks and warns you if a duplicate or
`nonreserved address is entered.
`
`" Unique Identifier usually specifies the media access control (MAC) address for the
`client computer's network adapter card. You can determine this address by typing net
`config wksta at the command prompt on the client computer.
`
`' Client Name specifies the computer name for this client. This is used for identification
`purposes only and does not affect the actual computer name for the client. This is not
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 110
`
`

`
`available for MS—DOSbased clients; in this case, only the Unique identifier appears.
`
`' Client Comment is any optional text that you enter to describe this client.
`
`3. Choose the Add button to add the reservation to the DHCP database. You can continue to
`
`add reservations without dismissing this dialog box.
`
`4. When you have added all reservations, choose the Close button.
`
`After the IP address is reserved in DHCP Manager, the client computer must be restarted to be
`configured with the new IP address.
`
`if you want to change a reserved IP address for a client, you have to remove the old reserved
`address and add a new reservation. You can change any other information about a reserved
`client while keeping the reserved IP address.
`
`F To change the reserved IP address
`
`1. Make sure the reserved client is not using the old IP address. To do this, shut down the
`client computer immediately after issuing the ip configlrelease command on that client
`computer.
`
`In the Active Leases dialog box, select the reserved IP address in the Client list, and
`choose the Delete button. Then choose the OK button.
`
`From the Scope menu, choose Add Reservations, and then enter information for a new
`reservation as described earlier in this section.
`
`F To change basic information for a reserved client
`
`1.
`
`2.
`
`From the Scope menu, choose Active Leases.
`
`In the Client list of the Active Leases dialog box, select the address of the reserved client
`that you want to change, and then choose the Properties button.
`
`In the Client Properties dialog box, change the unique identifier, client name, or comment,
`and then choose the OK button.
`
`Note
`
`You can only change values in the Client Properties dialog box for reserved clients.
`
`You can also view and change the options types that define configuration parameters for
`selected reserved clients by choosing the Options button in the Client Properties dialog box.
`Changing options for a reserved client follows the same procedure as use to originally define
`options, as described in "Defining Options for Reservations" earlier in this chapter.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 111
`
`

`
`.......................................................................................................................................................................................................................................................................................................................................................................................................................................................y
`
`Managing the DHCP Database Files
`
`The following files are stored in the \systemroot\SYSTEM32\DHCP directory that is created
`when you set up a DHCP server:
`
`' DHCP.MDB is the DHCP database file.
`
`' DHCP.TMP is a temporary file that DHCP creates for temporary database information.
`
`'
`
`'
`
`JET.LOG and the JET*.LOG files contain logs of all transactions done with the database.
`These files are used by DHCP to recover data if necessary.
`
`SYSTEM.MDB is used by DHCP for holding information about the structure of its database.
`
`Caution
`
`The DHCP.TMP, DHCP.MDB, JET.LOG, and SYSTEM.MDB files should not be removed or
`tampered with.
`
`The DHCP database and related Registry entries are backed up automatically at a specific
`interval (15 minutes by default), based on the value of Registry parameters (as described later
`in this chapter). You can also forced database backup while working in DHCP Manager.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 112
`
`

`
`i,’?...S,.t..‘.‘l.'.."..'79. ’.T‘.‘...CF’.Tl.f...i$'l‘.’...‘.'?9..'?H9.?._§?.fY.E{§%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%.
`Troubleshooting DHCP
`
`&&&&&&&&&&&&.,
`
`The following error conditions can appear to indicate potential problems with the DHCP server:
`
`'
`
`The administrator can't connect for a DHCP server using DHCP Manager. The message
`that appears might be, "The RPC server is unavailable."
`
`' DHCP clients cannot renew the leases for their lP addresses. The message that appears
`on the client computer is, "The DHCP client could not renew the IP address lease."
`
`'
`
`The DHCP Client service or Microsoft DHCP Server service may be down and cannot be
`restarted.
`
`The first task is to make sure the DHCP services are running.
`
`It To ensure the DHCP services are running
`
`1. Use the Services option in Control Panel to verify that the DHCP services are running.
`
`In the Services dialog box for the client computer, Started should appear in the Status
`column for the DHCP Client service. For the DHCP server itself, the Started should appear
`in the Status column for the Microsoft DHCP Server service.
`
`2.
`
`If a necessary service is not started on either computer, start the service.
`
`In rare circumstances, the DHCP server may not boot or a STOP error may occur. If the DHCP
`server is down, follow these steps to restart.
`
`'’ To restart a DHCP server that is down
`
`1. Turn off the power to the server and wait one minute.
`
`2. Turn on the power, start Windows NT Server, and log on under an account with
`Administrator rights.
`
`3. At the command prompt, type net start dhcpserver and press Enter.
`
`Note
`
`Use Event Viewer to find the possible source of problems with DHCP services.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 113
`
`

`
`. installing and Configuring DHCP Servers V
`......................
`
`Restoring the DHCP Database
`
`_
`
`20 of 33
`
`If you ascertain that the DHCP services are running on both the client and server computers
`but the error conditions described earlier persist, then the DHCP database is not available or
`has becomes corrupted. if a DHCP server fails for any reason, you can restore the database
`from the automatic backup files.
`
`5 To restore a DHCP database
`
`' Restart the DHCP server. if the DHCP database has become corrupted, it is automatically
`restored from the DHCP backup directory specified in the Registry, as described later in
`this chapter.
`
`F To force the restoration of a DHCP database
`
`'
`
`Set the value of RestoreFlag in the Registry to 1, and then restart the computer. For
`information about this parameter, see "Registry Parameters for DHCP Servers" later in this
`chapter.
`
`F To manually restore a DHCP database
`
`'
`
`If the two restore methods described earlier do not work, manually copy all DHCP
`database files from the backup directory to the \DHCP working directory. Then restart the
`Microsoft DHCP Server service.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 114
`
`

`
`Troubleshooting DHCP
`
`Backing up the DHCP Database onto Another Computer
`
`You may also find a situation where you need to backup a DHCP database to another
`computer. To do this, follow these steps.
`
`} To move a DHCP database
`
`' Use the Replicator service to copy the contents of the DHCP backup directory to the new
`computer.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 115
`
`

`
`-W§.i?"'i“9 3”?‘ 9°.".i..‘9F'”,"9 9.”? $?"’e’?" %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
`Advanced Configuration Parameters for DHCP
`
`%%%%%%%%%%%%
`
`This section presents configuration parameters that affect the behavior of DHCP servers and
`clients, and that can be modified only through Registry Editor. For the changes to take effect
`after you modify any of these value entries, you must restart the Microsoft DHCP Server
`service for server parameters or the DHCP Client service for client parameters.
`
`Caufion
`
`You can impair or disable Windows NT if you make incorrect changes in the Registry while
`using Registry Editor. Whenever possible, use DHCP Manager to make configuration changes,
`rather than using Registry Editor. lfyou make errors while changing values with Registry Editor,
`you will not be warned, because Registry Editor does not recognize semantic errors.
`
`F‘ To make changes to the DHCP server or client configuration using Registry Editor
`
`1. Run REGEDT32.EXE from File Manager or Program Manager, or at a command prompt,
`type start regedt32 and press ENTER.
`
`When the Registry Editor window appears, you can press F1 to get Help on how to make
`changes in Registry Editor.
`
`2.
`
`ln Registry Editor, click the window titled HKEY_LOCAL_MACHlNE on Local Machine, and
`then click the icons for the SYSTEM subtree until you reach the subkey for the specific
`parameter, as described in the following sections.
`
`The following sections describe the value entries for parameters for DHCP servers and clients
`that can be set only by adding an entry or changing their values in Registry Editor.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 116
`
`

`
`installing and_Configu_ring DHCP Servers
`
`A
`
`23 of33
`
`......................
`
`Registry Parameters DHCP Servers
`
`When you change any of these parameters except RestoreFlag, you must restart the
`computer for the changes to take effect. For the RestoreF|ag parameter, you must restart the
`Microsoft DHCP Server service.
`
`The Registry parameters for DHCP servers are specified under the following key:
`
`..SYSTEM\current\cu1‘rentcontro1set\services\DHCPServer\Parameters
`
`APIProtocolSupport
`
`Data type = REG_DWORD
`Range = OX1, OX2, OX4, OX5, OX7
`Default = OX1
`
`Specifies the supported protocols for the DHCP server. You can change this value to
`ensure that different computers running different protocols can access the DHCP server.
`The values for this parameter can be the following:
`
`OX1
`OX2
`OX4
`OX5
`
`OX7
`
`For RPC over TCPIP protocols
`For RPC over named pipes protocols
`For RPC over local procedure call (LPC) protocols
`For RPC over TCPIP and RPC over LPC
`
`For RPC over all three protocols (TCP/lP, named pipes, and LPG)
`
`BackupDatabasePath
`
`Data type = REG_EXPAND_SZ
`Range = filename
`Default = %SystemRoot%\system32\dhcp\backup
`
`Specifies the location of the backup database file where the database is backed up
`periodically. The best location for the backup file is on another hard drive, so that the
`database can be recovered in case of a system drive crash. Do not specify a network
`drive, because DHCP Manager cannot access a network drive for database backup and
`recovery.
`
`Backuplnterval
`
`Data type = REG_DWORD
`Range = no limit
`Default = 15 minutes
`
`Specifies the interval for backing up the database.
`
`Databasecleanuplnterval
`
`Data type = REG_DWORD
`Range = No limit
`Default = OX1518O (864,000 minutes - 24 hours)
`
`Specifies the interval for cleaning up expired client records from the DHCP database,
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 117
`
`

`
`freeing up those IP addresses for reuse.
`
`DatabaseLoggingFlag
`
`Data type = REG_DWORD
`Range = O or 1
`Default = 1 (true-that is, database logging is enabled)
`
`Specifies whether to record the database changes in the JET.LOG file. This log file is used
`after a system crash to recover changes that have not been made to the database file
`defined by DatabaseName. Database logging affects system performance, so
`DatabaseLogging can be turned off if you believe the system is highly stable and if
`logging is adversely affecting system performance.
`
`DatabaseName
`
`Data type = REG__SZ
`Range = f//ename
`Default = dhcp.mdb
`
`Specifies the name of the database file to be used for the DHCP client information
`database.
`
`DatabasePath
`
`Data type = REG_EXPAND_sZ
`Range = pathname
`Default = %SystemRoot%\System32\dhcp
`
`Specifies the location of the database files that have been created and opened.
`
`RestoreFlag
`
`Data type = REG_DWORD
`Range = O or 1
`Default = O (false-that is, do not restore)
`
`Specifies whether to restore the database from the backup directory. This flag is reset
`automatically after the successful restoration of the database.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 118
`
`

`
`............................................................................................................................................................................................................................................................................................................................................................................................................................................................t/
`
`Advanced Configuration Parameters for DHCP
`
`Registry Parameters for DHCP Clients
`
`The Registry parameters for DHCP clients are specified under the following key:
`
`..SYSTEM\current\currentcontro1set\services\DHCP\Parameter\<0ption#>
`The Opt/'on# keys are a list of DHCP options that the client can request from the DHCP server.
`For each of the default options, the following values are defined:
`
`Reg Location
`
`Data type = REG_SZ
`Default = Depends on the Registry location for the specific option
`
`Specifies the location in the Registry where the option value is written when it is obtained
`from the DHCP server. The "?" character expands to the adapter name for which this
`option value is obtained.
`
`KeyType
`
`Data type = REG_DWORD
`Default = OX7
`
`Specifies the type of Registry key for the option.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 119
`
`

`
`'s”?'‘*?''p‘.'‘9 3”“ iC°"s"9F'””9 DHCP Servers
`Guidelines for Setting Local Policies
`
`........?..g"is...‘.?.‘.rr"'s3
`
`This section provides some suggestions for setting lease options, dividing the free address
`pool among DHCP servers, and avoiding DNS naming problems.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 120
`
`

`
`B. Installing and Configuring DHCP Servers
`rrrrrrrrrrrrrrr
`
`26 of 33
`
`A
`
`_
`.. __
`
`..
`
`Guidelines for Managing DHCP Addressing Policy
`
`Allocation of IP addresses for distribution by DHCP servers can be done dynamically or
`manually. These methods use the same DHCP client~server protocol, but the network
`administrator manages them differently at the DHCP server.
`
`Dynamic Allocation of IP Addresses
`
`Dynamic allocation allows a client to be assigned an IP address from the free address pool.
`The lease for the address has a lease duration (expiration date), before which the client must
`renew the lease to continue using that address. Depending on the local lease policies defined
`by the administrator, dynamically allocated addresses can be returned to the free address pool
`if the client computer is not being used, if it is moved to another subnet, or if its lease expires.
`Any IP addresses that are returned to the free address pool can be reused by the DHCP server
`when allocating an IP address to a new client. Usually the local policy ensures that the same IP
`address is assigned to a client each time that system starts and that addresses returned to the
`pool are reassigned.
`
`After the renewal time of the lease time has passed, the DHCP client enters the renewing state
`(as described in Chapter 3, "Networking Concepts for TCP/|P"). The client sends a request
`message to the DHCP server that provided its configuration information. lfthe request for a
`lease extension fits the local lease policy, the DHCP server sends an acknowledgment that
`contains the new lease and configuration parameters. The client then updates its configuration
`values and returns to the bound state.
`
`When the DHCP client is in the renewing state, it must release its address immediately in the
`rare event that the DHCP server sends a negative acknowledgment. The DHCP server sends
`this message to inform a client that it has incorrect configuration information, forcing it to
`release its current address and acquire new information.
`
`If the DHCP client cannot successfully renew its lease, the client enters a rebinding state. At
`this stage, the client sends a request message to all DHCP servers in its range, attempting to
`renew its lease. Any server that can extend the lease sends an acknowledgment containing the
`extended lease and updated configuration information. If the lease expires or if a DHCP server
`responds with a negative acknowledgment, the client must release its current configuration and
`return to the initializing state. (This happens automatically, for example, for a computer that is
`moved from one subnet to another.)
`
`lfthe DHCP client uses more than one network adapter to connect to multiple networks, this
`protocol is followed for each adapter that the user wants to configure for TCP/lP. Windows NT
`allows multihomed systems to selectively configure any combination of the system's interfaces.
`You can use the ipconfig utility to view the local IP configuration for a client computer.
`
`When a DHCP-enabled computer is restarted, it sends a message to the DHCP server with its
`current configuration information. The DHCP server either confirms this configuration or sends
`a negative reply so that the client must begin the initializing stage again. System startup might
`therefore result in a new IP address for a client computer, but neither the user nor the network
`administrator has to take any action in the configuration process.
`
`Manual Allocation of IP Addresses
`
`Manual allocation follows the iolici used in most current TCP/lP imi|ementations.-
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 121
`
`

`
`Any IP
`addresses assigned in this way cannot be allocated by DHCP servers to other clients using
`either automatic or dynamic allocation. The address has a permanent lease.
`
`For example, for the range of IP addresses to be provided through RAS servers, these
`addresses should be manually excluded from the range of dynamically allocated addresses.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 122
`
`

`
`. Installing and Configuring DHCP Servers
`..............
`
`Guidelines for Lease Options
`
`27o_f 33
`
`..
`
`_
`
`.
`
`.
`
`To define appropriate values for lease duration, you should consider the frequency of the
`following events for your network:
`
`' Changes to DHCP options and default values
`' Network interface failures
`
`" Computer removals for any purpose
`
`'
`
`Subnet changes by users because of office moves, laptop computers docked at different
`workstations, and so on
`
`All of these types of events cause IP addresses to be released by the client or cause the
`leases to expire at the DHCP server. Consequently, the IP addresses will be returned to the
`free address pool to be reused.
`
`if many changes occur on your internetwork, you should assign short lease times, such as two
`weeks. This way, the addresses assigned to systems that leave the subnet can be reassigned
`quickly to new DHCP client computers requesting TCP/lP configuration information.
`
`Another important factor is the ratio between connected computers and available IP addresses.
`For example, the demand for reusing addresses is low in a network where 40 systems share a
`class C address (with 254 available addresses). A long lease time such as two months would
`be appropriate in such a situation. However, if 230 computers share the same address pool,
`demand for available addresses is much greater, so a lease time of a few days or weeks is
`more appropriate.
`
`Notice, however, that short lease durations require that the DHCP server be available when the
`client seeks to renew the lease. So backup servers are especially important when short lease
`durations are specified.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 123
`
`

`
`V installing and ConfiguringDHCP Servers _
`.
`......
`Guidelines for Partitioning the Address Pool
`
`_
`
`28 of_33
`.................................................................... ..
`
`You will probably decide to install more than one DHCP server, so the failure of any individual
`server will not prevent DHCP clients from starting. However, DHCP does not provide a way for
`DHCP servers to cooperate in ensuring that assigned addresses are unique. Therefore, you
`must divide the available address pool among the DHCP servers to prevent duplicate address
`assignment.
`
`A typical scenario is a local DHCP server that maintains TCP/IP configuration information for
`two subnets. For each DHCP server, the network administrator allocates 70 percent of the IP
`address pool for local clients and 30 percent for clients from the remote subnet, and then
`configures a relay agent to deliver requests between the subnets.
`
`This scenario allows the local DHCP server to respond to requests from local DHCP clients
`most of the time. The remote DHCP server will assign addresses to clients on the other subnet
`only when the local server is not available or is out of addresses. This same method of
`partitioning among subnets can be used in a multiple subnet scenario to ensure the availability
`of a responding server when a DHCP client requests configuration information.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 124
`
`

`
`, installing and Configuring DHCP Servers
`...................
`
`H
`
`g
`
`V
`
`V 29 of 33
`
`Guidelines for Avoiding DNS Naming Conflicts
`
`DNS can be used to provide names for network resources, as described in Chapter 3,
`"Networking Concepts for TCP/lP." However, DNS configuration is static. With DHCP, a host
`can easily have a different IP address if its lease expires or for other reasons, but there is no
`standard for updating DNS servers dynamically when IP address information changes.
`Therefore, DNS naming conflicts can occur if you are using DHCP for dynamic allocation of IP
`addresses.
`
`This problem will primarily affect systems that extend internetworking services to local network
`users. For example, a server acting as an anonymous FTP server or as an e-mail gateway
`might require users to contact it using DNS names. In such cases, such clients should have
`reserved leases with an unlimited duration.
`
`For workstations in environments that do not require the computers to register in the DNS
`name space, DHCP dynamic allocation can be used without problems.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 125
`
`

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`Guidelines for Setting Local Policies
`
`Using DHCP with Diskless Workstations
`
`if your network includes diskless workstations or X terminal BOOTP clients that need
`configuration information to use TCP/IP, you must build profiles. (BOOTP is the
`internetworking Bootstrap Protocol used to configure systems across internetworks. DHCP is
`an extension of BOOTP.)
`
`You might decide to continue to manage these workstations using your existing BOOTP
`servers. if so, you must be sure to exclude these addresses from the free address pool
`maintained by the DHCP server.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 126
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`

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`'"$ta"l"9 ?"‘.d ‘?9“f..i.9.“”'l9 DH9.l?...,S?.'fY.S?.T§..................................................................
`Planning a Strategy for DHCP
`
`.....
`
`This section describes how to develop strategies for placing DHCP servers on smaII—scale and
`large-scale installations. Most network administrators implementing DHCP will also be planning
`a strategy for implementing WINS servers. The planning tasks described here also apply for
`WINS servers, and in fact, the administrator will probably want to plan DHCP and WINS
`implementation in tandem.
`
`The following describes the general planning tasks:
`
`1. Compile a list of a requirements, including:
`
`'
`
`"
`
`Client support (numbers and kinds of systems to be supported)
`
`Interoperability with existing systems, especially requirements for mission—critical
`accounting, personnel, and similar information systems
`
`' Hardware support and related software compatibility (including routers, switches, and
`servers)
`
`" Network monitoring software, including SNMP requirements and other tools
`
`2.
`
`Isolate the areas of the network where processes must continue uninterrupted, and target
`these areas for the last stages of implementation.
`
`3. Review the geographic and physical structure of the network to determine the best plan for
`defining logical subnets as segments of the internetwork.
`
`4. Define the components in the new system that require testing, and develop a phase plan
`for testing and adding components.
`
`For example, the plan could define units of the organization to be phased into using DHCP,
`and the order for types of computers to be phased in (including Windows NT servers and
`workstations, Microsoft RAS servers and clients, Windows for Workgroups computers, and
`MS—DOS clients).
`
`5. Create a pilot project for testing. Be sure that the pilot project addresses all the
`requirements identified in Task #1.
`
`6. Create a second test phase, including tuning the DHCP (and WINS) server-client
`configuration for efficiency. This task can include determining strategies for backup servers
`and for partitioning the address pool at each server to be provided to local versus remote
`clients.
`
`7. Document all architecture and administration issues for network administrators.
`
`8.
`
`Implement a final phase for bringing all organizational units into using DHCP.
`
`While planning, remember that the actual placement of the servers in the physical network
`need not be a major planning issue. DHCP servers (and WINS servers) do not participate in
`the Windows NT Server domain model, so domain membership is not an issue in planning for
`server placement. Because most routers can forward DHCP configuration requests, DHCP
`servers are not required on every subnet in the internetwork. Also, because these servers can
`be administered remotely from any Windows NT Server computer that is DHCP- or
`WlNS—enabled, location is not a major issue in planning for server placement.
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 127
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`

`
`, Installing and Configuring l.')HCP Servers
`..................
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`H
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`132 of 33
`
`Planning a Small—Sca|e Strategy for DHCP Servers
`
`For a small LAN that does not include routers and subnetting, the server needs for the network
`can probably be provided with a single DHCP server.
`
`Planning in this case includes determining the following:
`
`' The hardware and storage requirements for the DHCP server
`
`' Which computers can immediately become DHCP clients for dynamic addressing and
`which should keep their static addresses
`
`' The DHCP option types and their values to be predefined for the DHCP clients
`
`DHCP server
`
` £IP aztlress
`
`D HCP clients
`
`A Single Local Network Using Automatic TCP/IP Configuration with DHCP
`
`Petitioner Sipnet EU S.R.O. - Exhibit 1019 - Page 128
`
`

`
`Planning a Strategy for DHCP
`
`Planning a Large-Scale Strategy for DHCP Servers
`
`The network administrator can use relay agents implementing RFC 1542 (usually IP routers)
`so that DHCP servers located on one node of the internetwork can respond to TCP/lP
`configuration requests from remote nodes. The relay agent forwards requests from local DHCP
`clients to the DHCP server and subsequently relays responses back to the clients.
`
`‘ffitfi DHCP clients
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`database
`
`An Internetwork Using Automatic TCP/lP Configuration with DHCP
`
`The additional planning issues for a large enterprise network includes:
`
`" Compatibility of hardware and software routers with DHCP, as described at the beginning
`of this chapter.
`
`'
`
`"
`
`Planning the physical subnetting of the network and relative placement of DHCP servers.
`This includes planning for placement of DHCP (and WINS servers) among subnets in a
`way that reduces b-node broadcasts across routers.
`
`Specifying the DHCP option types and their values to be predefined per scope for the
`DHCP clients. This may include planning for scopes based on the needs of particular
`groups of users. For example, for a marketing group that uses portable computers docke