1.2.1.5.2 DHCP Server V2 Configurations

DHCP Server V2 Specific User Configurations

  • Maximum Number Leases per Interface:

    • Specifies the maximum number of leases that the DHCP server can support for an interface

    • The actual number of leases per interface could be smaller than this

    • Multiple of 32

    • Default value 32

    • Symbol TCPIP_DHCPS_MAX_LEASES

  • Number of ICMP Echo Probes:

    • Number of ICMP echo probes to send when doing address conflict detection

    • Default value 1

  • Number of Conflict Attempts for new IP Address:

    • Number of attempts to find a new IP address when ICMP detected an address conflict

    • Default value 1

  • Number of Leases:

    • Maximum number of leases for this interface

    • Must be <= TCPIP_DHCPS_MAX_LEASES

  • Default Lease Duration(in Sec):

    • Default lease duration to be granted to clients, seconds

    • Default value 28800 seconds (8 hours)

  • DHCPS Server IP Address:

    • Server IP address on this interface

  • Lease IP Address Starting from:

    • Start lease IP address

    • The pool of addresses will be

    • where endIPAddress is given by the prefixLen

  • Prefix Length (CIDR notation):

    • The number of the leading 1 bits in the network mask

    • number <= 32

    • the address is specified in the CIDR format: add/prefix_len

    • the maximum size of the pool is dictated by the prefixLen

    • For example: 192.168.0.0/24 will have 254 leases available

    • (192.168.0.0 and 192.168.0.255 are excluded)

    • and endIPAddress == 192.168.0.254

    • Note: the number of possible leases == min(leaseEntries, endIPAddress - startIPAddress).

    • The number of leases derived from startIPAddress/prefixLen should be > leaseEntries.

  • Client Options:

    • DHCP server configuration of provided client options

    • Lists the options to be presented to clients requiring an address lease

    • Router IP Address:

      • Provide router/gateway option

    • DNS IP Address:

      • Provide DNS option

    • Time Server IP Address:

      • Provide time server option

    • Name Server IP Address:

      • Provide name server option

    • NTP Server IP Address:

      • Provide NTP server option

  • Configuration Flags:

    • Disabled at Start of Interface:

      • DHCP server should start disabled on this interface

      • Note: this setting is currently not used and overridden by the

      • TCPIP_NETWORK_CONFIG:: startFlags.TCPIP_NETWORK_CONFIG_DHCP_SERVER_ON

    • Delete Lease Info on Restart:

      • DHCP server should delete the existent info for leases

      • when the interface is restarted

    • Disable Conflict Detection:

      • Disable DHCP server conflict detection of newly allocated addresses

      • By default the server should send an ICMP echo request when using a new IP address

    • Disable Lease Extension Request:

      • Disable DHCP clients request for extending the lease

      • By default the server grants lease extension to the clients

    • Keep Info of Not Requested Offers:

      • Keep DB info for offers that have not been requested by the client

      • i.e. when client selected another server (multi-server environment)

      • By default the info for these clients is deleted to free some space in the DB

    • ICMP Probe Failure Abort:

      • When DHCP server conflict detection is enabled, if sending echo requests failed

      • (ICMP module rejected the calls, TCPIP_DHCPS_EVENT_ECHO_FAIL event)

      • abort offering the lease to the client.

      • By default the server will send the offer to the client

    • Keep Silent if No Record:

      • Keep silent when receiving a client request for which there is no previous record

      • (i.e. do not verify the requested IP address and send NAK, etc.)

      • By default the server will reply with NAK if the requested lease is invalid

  • Minimum Lease Duration(in Sec):

    • Minimum lease duration that can be requested by a client, seconds

    • If 0, then a default of 60 seconds will be used

    • Should be <= leaseDuration

  • Maximum Lease Duration(in Sec):

    • Maximum lease duration that can be requested by a client, seconds

    • If 0, then the leaseDuration will be used

    • Should be >= leaseDuration

  • Unrequested Offer Timeout(in Sec):

    • Timeout for unrequested offer sent to the client, seconds

    • Note: used if TCPIP_DHCPS_CONFIG_FLAG_KEEP_UNREQ_OFFERS is not set

    • If 0, a default of 5 seconds will be used

  • T1 Renewal Time Calculation:

    • Timeout used for TCPIP_DHCPS_CLIENT_OPTION_T1_RENEWAL

    • Multiplication/Division Factors:

      • The multiplication/division factors of T1

      • The T1 is obtained as percentages of lease time:

      • T1 = (leaseTime * mult) / div; default values are mult = 1, div = 2;

      • Default values are used for mult or div if any of them are 0

      • T2 needs to be greater than T1!

  • T2 Rebind Time Calculation:

    • Timeout used for TCPIP_DHCPS_CLIENT_OPTION_T2_REBINDING

    • Multiplication/Division Factors:

      • The multiplication/division factors of T2

      • The T2 is obtained as percentages of lease time:

      • T2 = (leaseTime * mult) / div; default values are mult = 7, div = 8;

      • Default values are used for mult or div if any of them are 0

      • T2 needs to be greater than T1!

  • DHCP Server Interface Count:

    • Maximum number of interfaces on which DHCPs could run

    • Note that this could be less than the maximum number of interfaces in the stack for this build (TCPIP_STACK_NETWORK_INTERAFCE_COUNT)!

    • Symbol: TCPIP_DHCPS_INTERFACE_COUNT

  • DHCP Server Task Rate (in msec):

    • DHCPS task processing rate, in milliseconds.

    • The DHCPS module will process a timer event with this rate for maintaining its own queues, processing timeouts, etc.

    • Choose it so that the other TMO are multiple of this

    • The default value is 200 milliseconds.

    • The lower the rate (higher the frequency) the higher the module priority and higher module performance can be obtained

    • The value cannot be lower than the TCPIP_STACK_TICK_RATE.

  • Client ID Maximum Size:

    • Maximum size of the client identifier field

    • Needs to be >= size of a MAC Address

    • Note: when a client is requesting a lease using a longer client ID the ID will be truncated!

  • ICMP Echo Request Buffer Size:

    • Size of the buffer when sending a ICMP echo request for address conflict detection

    • Should be between 8 and 32 bytes

    • Default value is 16

  • Number of ICMP Request Retries:

    • Number of retries if ICMP is not able to send a ping

    • This should only happen if there are too many ICMP echo requests ongoing

    • Default value is 2

  • Maximum Number of Router Value Options:

    • Maximum number of values for the options to be sent to clients

    • A value defined as 0 excludes that option

  • Maximum Number of DNS Value Options:

    • Maximum number of values for the options to be sent to clients

    • A value defined as 0 excludes that option

  • Maximum Number of Time Server Value Options:

    • Maximum number of values for the options to be sent to clients

    • A value defined as 0 excludes that option

  • Maximum Number of Name Server Value Options:

    • Maximum number of values for the options to be sent to clients

    • A value defined as 0 excludes that option

  • Maximum Number of NTP Server Value Options:

    • Maximum number of values for the options to be sent to clients

    • A value defined as 0 excludes that option

  • Suppress T1 Renewal and T2 Rebind:

    • Suppress the 'renewal T1' and 'rebinding T2' options when replying to a client request

    • By default these options are enabled

  • Maximum Number of Event Registrations:

    • Maximum number of event registrations

    • If 0 or not defined, there is no event registration

  • Enable Error Events Report:

    • Enable the report of error events using the event notification mechanism

  • Enable Client Events Report:

    • Enable the report of client events using the event notification mechanism

  • Enable Statistics:

    • Maintain DHCPs statistics counts

    • Symbol TCPIP_DHCPS_ENABLE_STATISTICS

  • Enable Dynamic DB Manipulation:

    • Allow dynamic manipulation of the DHCPs DB

    • Symbol TCPIP_DHCPS_DYNAMIC_DB_ACCESS

  • Enable Multi-Threaded Access:

    • Enable multi-threaded access

    • Symbol TCPIP_DHCPS_MULTI_THREADED_ACCESS

  • DHCP Server Heap Size (bytes):

    • An estimation of the heap required by the DHCP server