Expand description
A client cache.
This module implements a simple message cache provided as a pass through transport. The cache works with any of the other transports. The basic operation is that from a request the query name, class, and type are extracted and the result is cached such that when a new request arrives with the same name, class, and type then the cached response can be returned with the TTL values of the DNS resource records reduced by the amount of time the message has been cached.
The response to a query is in general affected by four flags: the AD, CD, DO, and RD flags. These flags are defined in the following RFCs: RFC 1035, RFC 2535, RFC 3225, RFC 4035, RFC 6840. The cache takes these flags into account to see if a cached response can be returned. In some cases, a cached response with one set of flags can be made suitable for a query with different flags.
The Config object provides various configuration options, such as the maximum number of cache entries, how long different types of responses should be cached and whether truncated responses should be cached or not.
Structsยง
- Configuration of a cache.
- A connection that caches responses from an upstream connection.
- The state of a request that is executed.