DNS Testbed

DNS testbed is an environment to test dns zone configurations and queries. A testbed consists of one or more zones, one or more resolvers and one client. The client can query the resolver for zones provided by target.com or inter.net. The resolver then resolves that query recursively according to the DNS specifications. We provide a simple command line interface to:

• initialize a custom testbed
• change zone configurations
• delay zone responses
• flush the resolvers cache
• query a resolver for a dns record and measure the query duration or query volume at a specific component

We also provide functionallity to run a series of dns queries and measurements with different testbed settings such as different zone configurations and delays.

Setup

The testbed runs in docker. We use a seperate container for every resolver and one container per nameserver. A nameserver can host multiple zones. The nameservers run bind9 (version bind-9.18.4). We provide different implementations for resolvers. The implementation and version can be specified in the testbed configuration file. Currently, the following implementations are supported:

• bind
• unbound
• powerDNS (only major versions are supported: 4.2 - 4.7)

The client is a container running dig to submit the DNS queries.

Installation

1. Install Docker

2. Install docker-compose

3. Download and install go (requires go1.18)

4. Inside the project root run

   $ go mod tidy
   $ go install
   

5. Might need to set GOPATH and add it to PATH:

   $ export GOPATH=$(go env GOPATH)
   $ export PATH=$GOPATH/bin:$PATH
   

Usage

Initialization

A new testbed can be initialized by providing a .yaml file containing the configuration of the testbed. The configuration file should be structured as follows:

root: "172.20.0.2"
nameservers:
  - id: "root"
    ip: "172.20.0.2"
    zones:
      - qname: "."
  [...]

resolvers:
- implementation: "bind"
  version: "9.18.4"
  ip: "172.20.0.51"
  [...]

client:
  id: "client"
  ip: "172.20.0.99"
  nameserver: "172.20.0.51"

We provide an example configuration in the example directory.

Start

To initialize and start a testbed run

$ testbed init example/testbed.yaml
$ testbed start

Make sure that docker desktop is running.

Manual Usage

For the full list of commands run testbed -h:

Usage:
  testbed [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  delay       Delay the responses of a zone by the specified duration (in ms)
  flush       Flush the cache of all resolvers
  help        Help about any command
  init        Initialize a dns testbed
  query       Query a resolver for a specific qname and record
  run         Run an experiment according to the specified configuration
  start       Build and run the dns testbed
  stop        Stop the dns testbed
  zones       Set zone files

Flags:
  -h, --help   help for testbed

Use "testbed [command] --help" for more information about a command.

DNS experiment

We define a dns experiment to be a series of dns measurements. To run a dns measurement a .yaml file with the configuration of the experiment has to be provided.

name:            string, name of the experiment
resolverIDs:     []string, ids of resolvers to query
zonesDir:        path, path to zone configurations; 
	         the zone files should be named after the id of the zone
	         and be collected in a directory specifying the measurement; e.g.
	         /zonesDir
	              /1
	                   target-com.zone
	                   inter-net.zone
	              /n
                      ...
target:          string, specifying the component where to measure the query volume or duration
measure:         ["volume", "duration"], specifying the kind of measurement
query:
  recordType:    string (default="A")
  qname:         string
qmin:            bool (default=false), whether qmin is enabled
delay:           []int (default=[0]), delays to be set at the delayedZones before measurements
delayedZones:    []string
warmup:          []string, list of qnames to query before a measurement to warm up the resolver
dest:            path, location where to save the results
saveLogs:        bool, whether to save the logs
testbed:   path, path to yaml file with testbed configuration

Run the experiment with the following command

testbed run example/experiment.yaml

We provide an example configuration in the example directory.

Some commands require specifying the id of the component. For the zones the id corresponds to the qname with intermediary dots replaced by dashes. Zone files must always be named after the id of the respective zone.

qname	id
.	root
.com	com
target.com	target-com

The id of the resolvers corresponds to the concatenation of the identifier resolver, the implementation and the version.

implementation	version	id
bind	9.18.4	resolver-bind-9.18.4
unbound	1.10.0	resolver-unbound-1.10.0