dns-performance-test

This script will query DNS servers with a provided query list and measure the response time.

Device Identification

In order to track multiple results from different hosts, the hostname and a unique ID is gathered from each host where the script runs.

For the UUID, when the script runs for it's initial attempt, it'll try and see if there's a uuid.cfg file.

• If there is a uuid.cfg file, it'll read the contents and use that for identification.
• if there is not a uuid.cfg file, it'll create a new uuid and write that to uuid.cfg.

UUID

To read the current UUID for the device:

python3 dns-resolution-test.py --getUuid

To delete the UUID, ether remove the uuid.cfg file, or run the command:

python3 dns-resolution-test.py --deleteUuid

To renew/reset the UUID:

python3 dns-resolution-test.py --renewUuid

Tags

If you want to tag your results for aggregating data across multiple devices, do the following:

python3 dns-resolution-test.py --setTag <TAGNAME>

If there's no tag.cfg file, then deviceTag in the output.json file is "".

If you want to remove the tag, either remove the tag.cfg file or:

python3 dns-resolution-test.py --deleteTag

To display the current tag:

python3 dns-resolution-test.py --getTag

Reference files

By default, it'll read the inputs from filenames:

• nameservers.txt - list of DNS nameservers to query
• queries.txt - list of queries to perform on the DNS nameservers.

It will also by default not create any output (file, stdout, other).

The queries file will accept entries in the following formats:

test.com
123.123.123.123,ptr
abc.com,a
cnn.com,mx
google.com,aaaa

If an entry has an incorrect DNS query type, for example - referencing 'aaa' (invalid) instead of 'aaaa' (valid IPv6 query type), the program will not stop, but will report an error and continue to the next entry.

Arguments

If you want output there are some options available (in any combination):

  --ifname IFNAME      List of nameserver IP addresses file, each entry on a new line. This can be a URL as well.
  --ifquery IFQUERY    List of queries file to be performed, each entry on a new line. This can be a URL as well.
  --ofresults          JSON results output file (uuid,tag,script start time, script end time, results)
  --jsonstdout         print results to stdout
  --displayResponses   Display formatted results
  --verbose            Displays the response times of all the tests.
  --setTag SETTAG      Set the tag for the query results. Creates tag.cfg file with tag.
  --deleteTag          Delete the tag file - tag.cfg
  --getTag             Get the tag from tag.cfg file
  --renewUuid          Renew the UUID value.
  --getUuid            Get the UUID value from uuid.cfg file.
  --deleteUuid         Remove the UUID value. Caution: when script runs again a new UUID will be generated.
  --httpPOST HTTPPOST  Upload the JSON results to the URL

JSON Sample format

{
  "deviceUuid": "<UUID>",
  "hostName": "<HOSTNAME>",
  "deviceTag": "<DEVICETAG>",
  "scriptUTCStartTime": "<Script start time in UTC Format>",
  "scriptUTCEndTime": "<Script end time in UTC Format>",
  "dataFormatVersion": 3,
  "queryResults": {
    "dnsNameServerIP": [
      {
        "query": {
          "queryType": "hostname.example"
        },
        "response": [
          "<IP1>"
        ],
        "responseTime": "<Time in Milliseconds for response>",
        "responseTTL": <time_in_seconds_from_nameserver>
      },
      {
        "query": {
          "queryType": "hostname2.example2"
        },
        "response": [
          "<IP1>",
          "<IP2>"
        ],
        "responseTime": "<Time in Millseconds for response>",
        "responseTTL": <time_in_seconds_from_nameserver>
      },
      {
        "query": {
          "queryType": "hostname3.example3"
        },
        "response": [
          "<IP1>",
          "<IP2>",
          "<IP3>",
          "<IP4>"
        ],
        "responseTime": "<Time in Millseconds for response>",
        "responseTTL": <time_in_seconds_from_nameserver>
      }
    ]
  }
}

Actual Sample Result:

{
  "deviceUuid": "c166d274-2fca-42c2-9a26-d1887ca97bb2",
  "hostName": "myTestHost",
  "deviceTag": "production",
  "scriptStartTime": "2021-05-22 20:25:49.706083",
  "scriptEndTime": "2021-05-22 20:25:49.748855",
  "dataFormatVersion": 3,
  "queryResults": {
    "8.8.8.8": [
      {
        "query": {
          "a": "test.com"
        },
        "response": [
          "69.172.200.235"
        ],
        "responseTime": "7.1",
        "responseTTL": 311
      },
      {
        "query": {
          "a": "google.com"
        },
        "response": [
          "142.250.217.110"
        ],
        "responseTime": "13.3",
        "responseTTL": 3429
      },
      {
        "query": {
          "a": "abc.com"
        },
        "response": [
          "99.84.73.44",
          "99.84.73.60",
          "99.84.73.41",
          "99.84.73.70"
        ],
        "responseTime": "21.8",
        "responseTTL": 151
      },
      {
        "query": {
          "mx": "testdomain.com"
        },
        "response": [
          "20 mail.testdomain.com.",
          "20 mail2.testdomain.com.",
          "30 mail3.testdomain.com."
        ]   
      }
    ]
  }
}

Future improvements:

• default list of nameservers and queries to be included in bundle
• ability to publish results to google sheets, ms excel online, etc.
• show if the DNS lookup is a PASS/FAIL based on evaluating criteria.
  • evaluation criteria:
    • ALL responses must be the same
    • ANY of the responses must be what we expect
  • ability to set an evaluation file based on immediate results for comparison later.
  • show current date, and delta compared to when initial evaluation file was created.
• support for DNSSEC queries