DNS: Difference between revisions
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* TC - Truncation Flag |
* TC - Truncation Flag |
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When set to 1, indicates that the message was truncated due to its length being longer than the maximum permitted for the type of transport mechanism used. |
When set to 1, indicates that the message was truncated due to its length being longer than the maximum permitted for the type of transport mechanism used. |
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TCP doesn't have a length limit for messages, while UDP messages are limited to 512 bytes |
TCP doesn't have a length limit for messages, while UDP messages are limited to 512 bytes. |
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So this bit being sent usually is an indication that the message was sent using UDP and was too long to fit. |
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The client may need to establish a TCP session to get the full message. |
The client may need to establish a TCP session to get the full message. |
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On the other hand, if the portion truncated was part of the Additional section, it may choose not to bother. |
On the other hand, if the portion truncated was part of the Additional section, it may choose not to bother. |