DNS Experiment
The DNS experiment blocks network traffic related to the Domain Name System (DNS). Port 53 is the IANA-assigned port for DNS traffic, so this experiment can be thought of as a Blackhole experiment on port 53. You can optionally specify IP addresses to block specific DNS providers.
This experiment has a built-in exception for resolving api.gremlin.com. This is so the Gremlin agent can remain in contact with the Gremlin Control Plane during the experiment. Without this exception, the agent’s failsafe will automatically trigger and halt the experiment.
Options
| Parameter |
Flag |
Default |
Version |
Description |
| IP Addresses |
-i IP address |
|
1.4.7 |
Only impact traffic to these IP addresses. Also accepts CIDR values (i.e.
10.0.0.0/24).
|
| Device |
-d interfaces |
Device discovery |
0.0.1 |
Impact traffic over these network interfaces. Comma separated lists and multiple arguments supported.
You can define multiple interfaces starting with agent version 2.30.0. |
| Protocol |
-P {TCP, UDP, ICMP} |
all |
1.4.7 |
Only impact a specific protocol. |
| Providers |
WebUI and API Only |
|
0.0.1 |
External service providers to affect. |
| Tags |
WebUI and API Only |
|
0.0.1 |
Only impact traffic to hosts running Gremlin clients associated with these tags. |
| Length |
-l int |
60 |
1.4.7 |
The length of the experiment (seconds). |
Privileges required
| Privilege |
Description |
| FAULT_DNS | Allows performing DNS experiments |
