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