dnstress is a tool that provides performance stress tests for defined DNS servers.
| Parameter | Description |
|---|---|
-c, --config=CONFIG |
File with a dnstress configuration (described in the section below) |
-l, --ld-lvl=LD-LVL |
Load level of stressing. The value has to be from 1 to 10. You can not use it with --rps option |
-r, --rps=RPS |
Number of requests per second. You can not use it with --ld-lvl option |
-m, --mode=MODE |
Traffic generation mode (udp-valid by default). Possible values are:
|
-o, --output=OUTFILE |
Output to OUTFILE instead of to standard output. This option isn't availbale for now |
-v, --verbose |
Produce verbose output. This option isn't availbale for now |
-V, --version |
Print program version |
First of all, dnstress uses a configuration file to setup some of internal structures. The default path is ./dnstress.json (it will be changed in the future). The example of a configuration file is shown below:
{
"addrs": [ "127.0.0.2", "127.0.0.3", "[2a0d:b600:166:ff00:e2d5:5eff:fe3a:a880]:1337" ],
"workers": 2,
"ttl": 20,
"queries": [
{ "dname": "google.com", "blocked": 0, "type": "AAAA" },
{ "dname": "vk.com", "blocked": 1, "type": "A" }
]
}dnstress is able to work with both UDP and TCP protocols. Which one to use (or both) is defined in the command line arguments. See Stress test modes for more information.
In the config file you can specify which queries will be used for stressing. You can specify them as follows:
"queries": [
{ "dname": "google.com", "blocked": 0, "type": "AAAA" },
{ "dname": "vk.com", "blocked": 1, "type": "A" }
]Some (happy) little explanation of object fields:
| Field | Description |
|---|---|
| dname | domain name string used for request |
| blocked | 1 if domain should be blocked by DNS server (only for statistics), 0 otherwise |
| type | type of request (A, AAAA, etc) for this specific domain name |
There are several executing modes that can be specified in the command line arguments before running dnstress. It's important to notice that every request is taken from the config file based on a stress test mode. All available modes are listed below:
| Mode | Description |
|---|---|
| udp-valid | UDP requests with blocked flag equals 0 |
| tcp-valid | TCP requests with blocked flag equals 0 |
| udp-nonvalid | UDP requests with blocked flag equals 1 |
| tcp-nonvalid | TCP requests with blocked flag equals 1 |
| shuffle | random choice of a query from the config file |
dnstress supports specifying a list of DNS servers. It is useful when your DNS server has several addresses and you want to check if all of them work correctly.
In the configuration file you can specify DNS server addresses as follows:
"addrs": [ "127.0.0.2", "127.0.0.3", "[2a0d:b600:166:ff00:e2d5:5eff:fe3a:a880]:1337" ] Notice that you can specify ports as well!
In the configuration file you can also specify number of workers. Worker here is a process that was forked from the parent process of dnstress. The more workers you specify, the more requests you will be producing.
Speify number of workers in the json config like that:
"workers": 2There is some limitation on the number of workers: from 1 to 10
ttl option allows you to specify the duration of a stressing (in seconds). If you specify ttl equals 0, then is means endless loop of sending requests. In this case you should stop dnstress by yourself.
"ttl": 20Of course, you still can stop dnstress in any time as well.
Before building dnstress, take a look at the requirements section. When all libraries are installed, type the next in the terminal to build or rebuild dnstress:
$ make clean && makeTo list all supported command line arguments, type --help:
$ ./dnstress --help
Usage: dnstress [OPTION...]
A program that provides performance stress tests for defined DNS servers.
-c, --config=CONFIG file with dnstress configuration
-l, --ld-lvl=LD-LVL load level. from 1 to 10
-m, --mode=MODE mode for traffic generating (low-valid by
default)
• udp-valid: UDP valid packets
• tcp-valid: TCP valid packets
• udp-nonvalid: UDP non-valid (to be blocked)
packets
• tcp-nonvalid: TCP non-valid (to be blocked)
packets
• shuffle: random packets generating
-o, --output=OUTFILE Output to OUTFILE instead of to standard output
-r, --rps=RPS number of requests per second
-v, --verbose produce verbose output
-?, --help Give this help list
--usage Give a short usage message
-V, --version Print program versionAs you can see, help is self-documented. You need to just specify desired options when you run dnstress. Defualt mode is udp-valid. Run it like this:
$ ./dnstress --m shuffle -r 1000
Enter Ctrl+C to stop dnstress
[+] process workers are starting...
proc-worker: 0 | starting dnstress...
proc-worker: 1 | starting dnstress...After you stop dnstress, all collected statistics will be printed on the screen. For example, this can be:
STRESS STATISTIC
├─ 127.0.0.2
│ ├─── UDP
│ │ ├── NETWORK
│ │ │ ├─ queries: 1200
│ │ │ ├─ responses: 770
│ │ │ └─ loss: 35.83%
│ │ │
│ │ └── RESPONSE CODES
│ │ ├─ noerr: 770
│ │ ├─ corrupted: 0
│ │ ├─ formaerr: 0
│ │ ├─ servfail: 0
│ │ └─ errors: 0.00%
│ │
│ └─── TCP
│ ├── NETWORK
│ │ ├─ queries: 1200
│ │ ├─ responses: 1163
│ │ └─ loss: 3.08%
│ │
│ └── RESPONSE CODES
│ ├─ noerr: 1163
│ ├─ corrupted: 0
│ ├─ formaerr: 0
│ ├─ servfail: 0
│ └─ errors: 0.00%
│
└─ [2a0d:b600:166:ff00:e2d5:5eff:fe3a:a880]:1337
├─── UDP
│ ├── NETWORK
│ │ ├─ queries: 1200
│ │ ├─ responses: 770
│ │ └─ loss: 35.83%
│ │
│ └── RESPONSE CODES
│ ├─ noerr: 770
│ ├─ corrupted: 0
│ ├─ formaerr: 0
│ ├─ servfail: 0
│ └─ errors: 0.00%
│
└─── TCP
├── NETWORK
│ ├─ queries: 1200
│ ├─ responses: 653
│ └─ loss: 45.58%
│
└── RESPONSE CODES
├─ noerr: 653
├─ corrupted: 0
├─ formaerr: 0
├─ servfail: 0
└─ errors: 0.00%
All logs are stored in syslog. Thus, you can observe them in runtime using the next command:
tail -f /var/log/syslog | grep dnstressThese libraries are necessary for building:
If you find any problem or bug, submit an issue about this problem. Also, if you think that a feature will be a nice addition to dnstress, do the same -- submit an issue and we will try to add your requested feature as soon as possible.
- Add an option to control intensity of stressing (for instance, number of requests per second)
- Add an option for verbose or compressed output
- Change default path to
dnstressconfiguration file - Debian package