perfdhcp - DHCP benchmarking tool
perfdhcp [-1] [-4 | -6] [-A encapsulation-level] [-b base] [-B] [-c] [-C separator] [-d drop-time] [-D max-drop] [-e lease-type] [-E time-offset] [-f renew-rate] [-F release-rate] [-g thread-mode] [-h] [-i] [-I ip-offset] [-J remote-address-list-file] [-l local-address|interface] [-L local-port] [-M mac-list-file] [-n num-request] [-N remote-port] [-O random-offset] [-o code,hexstring] [-p test-period] [-P preload] [-r rate] [-R num-clients] [-s seed] [-S srvid-offset] [–scenario name] [-t report] [-T template-file] [-u] [-v] [-W exit-wait-time] [-w script_name] [-x diagnostic-selector] [-X xid-offset] [server]
perfdhcp is a DHCP benchmarking tool. It provides a way to measure
the performance of DHCP servers by generating large amounts of traffic
from multiple simulated clients. It is able to test both IPv4 and IPv6
servers, and provides statistics concerning response times and the
number of requests that are dropped.
The tool supports two different scenarios, which offer certain behaviors to be tested.
By default (the basic scenario), tests are run using the full four-packet exchange sequence
(DORA for DHCPv4, SARR for DHCPv6). An option is provided to run tests
using the initial two-packet exchange (DO and SA) instead. It is also
possible to configure
perfdhcp to send DHCPv6 RENEW and RELEASE messages
at a specified rate, in parallel with the DHCPv6 four-way exchanges. By
default, if there is no response received with one second, a response is
considered lost and
perfdhcp continues with other transactions.
A second scenario, called avalanche, is selected via
It first sends the number of Discovery or Solicit messages specified by the
-R option; then
a retransmission (with an exponential back-off mechanism) is used for each simulated client, until all requests are
answered. It generates a report when all clients receive their addresses, or when
it is manually stopped. This scenario attempts to replicate a
case where the server is not able to handle the traffic swiftly
enough. Real clients will assume the packet or response was lost
and will retransmit, further increasing DHCP traffic. This is
sometimes called an avalanche effect, thus the scenario name.
-p is ignored in the avalanche scenario.
When running a performance test,
perfdhcp exchanges packets with
the server under test as quickly as possible, unless the
-r parameter is used to
limit the request rate. The length of the test can be limited by setting
a threshold on any or all of the number of requests made by
perfdhcp, the elapsed time, or the number of requests dropped by the
To allow the contents of packets sent to the server to be customized,
perfdhcp allows the specification of template files that determine
the contents of the packets. For example, the customized packet may
contain a DHCPv6 ORO to request a set of options to be returned by the
server, or it may contain the Client FQDN option to request that the server
perform DNS updates. This may be used to discover performance
bottlenecks for different server configurations (e.g. DDNS enabled or
Up to two template files can be specified on the command line, with each file representing the contents of a particular type of packet, and the type being determined by the test being carried out. For example, if testing DHCPv6:
With no template files specified on the command line,
perfdhcpgenerates both Solicit and Request packets.
With one template file specified, that file is used as the pattern for Solicit packets:
perfdhcpgenerates the Request packets.
With two template files given on the command line, the first is used as the pattern for Solicit packets, and the second as the pattern for Request packets.
(A similar determination applies to DHCPv4’s DHCPDISCOVER and DHCPREQUEST packets.)
The template file holds the DHCP packet, represented as a stream of ASCII
hexadecimal digits; it excludes any IP/UDP stack headers. The
template file must not contain any characters other than hexadecimal
digits and spaces. Spaces are discarded when the template file is parsed;
in the file,
12B4 is the same as
12 B4, which is the same as
1 2 B 4.
The template files should be used in conjunction with the command-line
parameters which specify offsets of the data fields being modified in
outbound packets. For example, the
-E time-offset switch specifies
the offset of the DHCPv6 Elapsed Time option in the packet template.
If the offset is specified,
perfdhcp injects the current elapsed-time
value into this field before sending the packet to the server.
In many scenarios,
perfdhcp needs to simulate multiple clients,
each having a unique client identifier. Since packets for each client are
generated from the same template file, it is necessary to randomize the
client identifier (or HW address in DHCPv4) in the packet created from
-O random-offset option allows specification of the offset in
the template where randomization should be performed. It is important to
note that this offset points to the end (not the beginning) of the
client identifier (or HW address field). The number of bytes being
randomized depends on the number of simulated clients. If the number of
simulated clients is between 1 and 255, only one byte (to which the
randomization offset points) is randomized. If the number of
simulated clients is between 256 and 65535, two bytes are
randomized. Note that the last two bytes of the client identifier are
randomized in this case: the byte which the randomization offset parameter
points to, and the one which precedes it (random-offset - 1). If the
number of simulated clients exceeds 65535, three bytes are
randomized, and so on.
perfdhcp can simulate traffic from multiple subnets by enabling option
-J and passing a path to a file that contains v4 or v6 addresses to be
used as relays in generated messages. That enables testing of vast numbers
of Kea shared networks. While testing DHCPv4, Kea should be started with the
KEA_TEST_SEND_RESPONSES_TO_SOURCE environment variable, to force Kea
to send generated messages to the source address of the incoming packet.
Templates may currently be used to generate packets being sent to the server in 4-way exchanges, i.e. Solicit, Request (DHCPv6) and DHCPDISCOVER, DHCPREQUEST (DHCPv4). They cannot be used when Renew or DHCPRELEASE packets are being sent.
server-idoption from the first received message.
Establishes DHCPv4 operation; this is the default. It is incompatible with the
Establishes DHCPv6 operation. It is incompatible with the
Indicates the base MAC or DUID used to simulate different clients. The basetype may be “mac” or “duid”. (The keyword “ether” may alternatively used for MAC.) The
-boption can be specified multiple times. The MAC address must consist of six octets separated by single (:) or double (::) colons; for example: mac=00:0c:01:02:03:04. The DUID value is a hexadecimal string; it must be at least six octets long and not longer than 64 bytes, and the length must be less than 128 hexadecimal digits. For example: duid=0101010101010101010110111F14.
Specifies the time after which a request is treated as having been lost. The value is given in seconds and may contain a fractional component. The default is 1.
Specifies the type of lease being requested from the server. It may be one of the following:
Only regular addresses (v4 or v6) are requested.
Only IPv6 prefixes are requested.
Both IPv6 addresses and prefixes are requested.
-e address-and-prefixforms may not be used with the
Specifies the rate at which DHCPv4 DHCPRELEASE or DHCPv6 Release requests are sent to a server. This value is only valid when used in conjunction with the exchange rate (given by
-r rate). Furthermore, the sum of this value and the renew-rate (given by
-f rate) must be equal to or less than the exchange rate value.
Specifies the rate at which DHCPv4 DHCPREQUEST or DHCPv6 Renew requests are sent to a server. This value is only valid when used in conjunction with the exchange rate (given by
-r rate). Furthermore, the sum of this value and the release-rate (given by
-F rate) must be equal to or less than the exchange rate.
Allows selection of thread-mode, which can be either
multi. In multi-thread mode, packets are received in a separate thread, which allows better utilisation of CPUs. In a single-CPU system it is better to run in one thread, to avoid threads blocking each other. If more than one CPU is present in the system, multi-thread mode is the default; otherwise single-thread is the default.
Prints help and exits.
Performs only the initial part of the exchange: DISCOVER-OFFER if
-4is selected, Solicit-Advertise if
-iis incompatible with the following options:
-F. In addition, it cannot be used with multiple instances of
Specifies a text file that includes multiple addresses, and is designed to test shared networks. If provided,
perfdhcprandomly chooses one of the addresses for each exchange, to generate traffic from multiple subnets. When testing DHCPv4, it should be started with the
KEA_TEST_SEND_RESPONSES_TO_SOURCE=ENABLEenvironment variable; otherwise,
perfdhcpwill not be able to receive responses.
For DHCPv4 operation, specifies the local hostname/address to use when communicating with the server. By default, the interface address through which traffic would normally be routed to the server is used. For DHCPv6 operation, specifies the name of the network interface through which exchanges are initiated.
Specifies the local port to use. This must be zero or a positive integer up to 65535. A value of 0 (the default) allows
perfdhcpto choose its own port.
Specifies a text file containing a list of MAC addresses, one per line. If provided, a MAC address is chosen randomly from this list for every new exchange. In DHCPv6, MAC addresses are used to generate DUID-LLs. This parameter must not be used in conjunction with the
Specifies the remote port to use. This must be zero or a positive integer up to 65535. A value of 0 (the default) allows
perfdhcpto choose the standard service port.
perfdhcpto insert the specified extra option (or options if used several times) into packets being transmitted. The code specifies the option code and the hexstring is a hexadecimal string that defines the content of the option. Care should be taken as
perfdhcpdoes not offer any kind of logic behind those options; they are simply inserted into packets and sent as is. Be careful not to duplicate options that are already inserted. For example, to insert client class identifier (option code 60) with a string “docsis”, use “-o 60,646f63736973”. The
-omay be used multiple times. It is necessary to specify the protocol family (either
-6) before using
Initiates preload exchanges back-to-back at startup. Must be 0 (the default) or a positive integer.
Initiates the rate of DORA/SARR (or if
-iis given, DO/SA) exchanges per second. A periodic report is generated showing the number of exchanges which were not completed, as well as the average response latency. The program continues until interrupted, at which point a final report is generated.
Specifies how many different clients are used. With a value of 1 (the default), all requests appear to come from the same client. Must be a positive number.
Specifies the seed for randomization, making runs of
perfdhcprepeatable. This must be 0 or a positive integer. The value 0 means that a seed is not used; this is the default.
Specifies the type of scenario, and can be
basic(the default) or
Specifies a file containing the template to use as a stream of hexadecimal digits. This may be specified up to two times and controls the contents of the packets sent (see the “Templates” section above).
Enables checks for address uniqueness. The lease valid-lifetime should not be shorter than the test duration, and clients should not request an address more than once without releasing it.
Prints the version of this program.
Specifies the exit-wait-time parameter, which causes
perfdhcpto wait for a certain amount of time after an exit condition has been met, to receive all packets without sending any new packets. Expressed in microseconds. If not specified, 0 is used (i.e. exit immediately after exit conditions are met).
Specifies the name of the script to be run before/after
perfdhcp. When called, the script is passed a single parameter, either “start” or “stop”, indicating whether it is being called before or after
Includes extended diagnostics in the output. This is a string of single keywords specifying the operations for which verbose output is desired. The selector key letters are:
Prints the decoded command-line arguments.
Prints the exit reason.
Prints the rate-processing details.
Prints the received leases.
Prints the first server ID.
When finished, prints timers of all successful exchanges.
When finished, prints templates.
Time in seconds after which
perfdhcpstarts simulating the client waiting longer for server responses. This increases the
secsfield in DHCPv4 and sends increased values in the
Elapsed Timeoption in DHCPv6. Must be used with
Time in seconds during which
perfdhcpsimulates the client waiting longer for server responses. This increases the
secsfield in DHCPv4 and sends increased values in the
Elapsed Timeoption in DHCPv6. Must be used with
The following options only apply for DHCPv4 (i.e. when
-4 is given).
Forces broadcast handling.
The following options only apply for DHCPv6 (i.e. when
-6 is given).
Adds a rapid-commit option (exchanges are Solicit-Advertise).
Specifies that relayed traffic must be generated. The argument specifies the level of encapsulation, i.e. how many relay agents are simulated. Currently the only supported encapsulation-level value is 1, which means that the generated traffic is equivalent to the amount of traffic passing through a single relay agent.
Options Controlling a Test
Aborts the test immediately if “max-drop” requests have been dropped. Use
-D 0to abort if even a single request has been dropped. “max-drop” must be a positive integer. If “max-drop” includes the suffix
%, it specifies the maximum percentage of requests that may be dropped before aborting. In this case, testing of the threshold begins after 10 requests are expected to have been received.
Initiates “num-request” transactions. No report is generated until all transactions have been initiated/waited-for, after which a report is generated and the program terminates.
Sends requests for “test-period”, which is specified in the same manner as
-d. This can be used as an alternative to
-n, or both options can be given, in which case the testing is completed when either limit is reached.
Sets the delay (in seconds) between two successive reports.
Suppresses the preliminary output and causes the interim data to only contain the values delimited by
separator. Used in conjunction with
-tto produce easily parsable reports at
Indicates the server to test, specified as an IP address. In the DHCPv6 case, the special name
allcan be used to refer to
All_DHCP_Relay_Agents_and_Servers(the multicast address FF02::1:2), or the special name
serversto refer to
All_DHCP_Servers(the multicast address FF05::1:3). The server is mandatory except where the
-loption is given to specify an interface, in which case it defaults to
perfdhcp can report the following errors in the packet exchange:
A message was received that was too short.
A message was received which does not match one sent to the server (i.e. it is a duplicate message, a message that has arrived after an excessive delay, or one that is just not recognized).
Local system limits have been reached when sending a message.
perfdhcp exits with one of the following status codes:
Error in command-line arguments.
No general failures in operation, but one or more exchanges were unsuccessful.
Here is an example that simulates regular DHCPv4 traffic of 100 DHCPv4 devices (-R 100), 10 packets per second (-r 10), shows the query/response rate details (-xi), shows a report every 2 seconds (-t 2), and sends the packets to the IP 192.0.2.1:
sudo perfdhcp -xi -t 2 -r 10 -R 100 192.0.2.1
Here’s a similar case, but for DHCPv6. Note that the DHCPv6 protocol uses link-local
addresses, so the interface (eth0 in this example) must be specified on which to send the
all is a convenience alias for
(the multicast address FF02::1:2). It is also possible to use the
to refer to
All_DHCP_Servers (the multicast address FF05::1:3). The default is
sudo perfdhcp -6 -xi -t 1 -r 1 -R 10 -l eth0 all
The following examples simulate normal DHCPv4 and DHCPv6 traffic that, after 3 seconds,
starts pretending not to receive any responses from the server for 10 seconds. The
DHCPv4 protocol signals this by an increased
secs field, while DHCPv6 uses the
Elapsed Time option. In real networks, this indicates that clients are not getting
responses in a timely matter. This can be used to simulate some HA scenarios, as Kea
secs field and
Elapsed Time option value as one of the indicators
that the HA partner is not responding. When enabled with
Elapsed Time values increase steadily.
sudo perfdhcp -xi -t 1 -r 1 -y 10 -Y 3 192.0.2.1 sudo perfdhcp -6 -xi -t 1 -r 1 -y 10 -Y 3 2001:db8::1
Kea comes with an extensive Kea Administrator Reference Manual that covers all aspects of running the Kea software - compilation, installation, configuration, configuration examples, and much more. Kea also features a Kea Messages Manual, which lists all possible messages Kea can print with a brief description for each of them. Both documents are available in various formats (.txt, .html, .pdf) with the Kea distribution. The Kea documentation is available at https://kea.readthedocs.io.
Kea source code is documented in the Kea Developer’s Guide, available at https://reports.kea.isc.org/dev_guide/.
The Kea project website is available at https://kea.isc.org.
Mailing Lists and Support
There are two public mailing lists available for the Kea project. kea-users (kea-users at lists.isc.org) is intended for Kea users, while kea-dev (kea-dev at lists.isc.org) is intended for Kea developers, prospective contributors, and other advanced users. Both lists are available at https://lists.isc.org. The community provides best-effort support on both of those lists.
ISC provides professional support for Kea services. See https://www.isc.org/kea/ for details.
perfdhcp tool was initially coded in October 2011 by John
DuBois, Francis Dupont, and Marcin Siodelski of ISC. Kea 1.0.0, which
perfdhcp, was released in December 2015.
kea-dhcp4(8), kea-dhcp6(8), kea-dhcp-ddns(8), kea-ctrl-agent(8), kea-admin(8), kea-netconf(8), keactrl(8), kea-lfc(8), Kea Administrator Reference Manual.