Empty1 - Empty Packet
This module is designed to send an empty response, composed entirely of an empty packet.
In both UDP and TCP modes, the client/resolver will receive only the UDP or TCP packet header without any data or payload.
Category: Empty responses
Format
empty1.yourdomain.com
This module has no parameters.
Examples
In this example, we request an empty packet as the response in UDP mode, resulting in the client making three attempts to resolve the error:
# dig empty1.yourdomain.com @127.0.0.1 ;; Warning: short (< header size) message received ;; communications error to 127.0.0.1#53: timed out ;; Warning: short (< header size) message received ;; communications error to 127.0.0.1#53: timed out ;; Warning: short (< header size) message received ;; communications error to 127.0.0.1#53: timed out ; <<>> DiG 9.18.10-2-Debian <<>> empty1.yourdomain.com @127.0.0.1 ;; global options: +cmd ;; no servers could be reached
In this case, we request an empty packet as the response in TCP mode, resulting in the client again making three attempts to resolve the error:
# dig empty1.yourdomain.com @127.0.0.1 +tcp ;; communications error to 127.0.0.1#53: end of file ;; communications error to 127.0.0.1#53: end of file ;; communications error to 127.0.0.1#53: end of file ; <<>> DiG 9.18.10-2-Debian <<>> empty1.yourdomain.com @127.0.0.1 +tcp ;; global options: +cmd ;; no servers could be reached
Like other features, you can append anything to the feature name to avoid receiving cached responses from the target DNS resolver. This forces the target resolver to actively communicate with our PolarDNS server instead of responding with cached answers. Using a random number is the most effective strategy:
# dig empty1${RANDOM}.yourdomain.com @10.211.55.2 ;; Warning: short (< header size) message received ;; communications error to 10.211.55.2#53: timed out ;; Warning: short (< header size) message received ;; communications error to 10.211.55.2#53: timed out ;; Warning: short (< header size) message received ;; communications error to 10.211.55.2#53: timed out ; <<>> DiG 9.18.10-2-Debian <<>> empty124422.yourdomain.com @10.211.55.2 ;; global options: +cmd ;; no servers could be reached
From the same category
- Close - Close the Connection
- Empty2 - Only NULL Bytes
- Empty3 - Only NULL Bytes (Suitable for TCP)
- Empty4 - Only Transaction ID and NULL Bytes
- Empty5 - Only DNS Header and NULL Bytes
- Empty6 - ANSWER Section Missing
- Empty7 - ANSWER Section Is NULL Bytes
- QueryBack1 - Query Reflection
- QueryBack2 - Query Reflection (Stripped)
- QueryBack3 - Query Reflection (To Port 53)
- QueryBack4 - Query Reflection (Random, to Port 53)
- Timeout - Do Not Respond