26 lines
1.6 KiB
Text
26 lines
1.6 KiB
Text
adns is a DNS resolver library and a collection of utilities that use the
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library. The adns library has the following features:
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* It is reasonably easy to use for simple programs which just want to
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translate names to addresses, look up MX records, etc.
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* It can be used in an asynchronous, non-blocking, manner. Many
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queries can be handled simultaneously.
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* Responses are decoded automatically into a natural representation
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for a C program - there is no need to deal with DNS packet formats.
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* Sanity checking (eg, name syntax checking, reverse/forward
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correspondence, CNAME pointing to CNAME) is performed automatically.
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* Time-to-live, CNAME and other similar information is returned in an
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easy-to-use form, without getting in the way.
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* There is no global state in the library; resolver state is an
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opaque data structure which the client creates explicitly. A
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program can have several instances of the resolver.
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* Errors are reported to the application in a way that distinguishes
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the various causes of failure properly.
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* Understands conventional resolv.conf, but this can overridden by
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environment variables.
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* Flexibility. For example, the application can tell adns to: ignore
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environment variables (for setuid programs), disable hostname
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syntax sanity checks to return arbitrary data, override or ignore
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resolv.conf in favour of supplied configuration, etc.
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* Believed to be correct ! For example, will correctly back off to
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TCP in case of long replies or queries, or to other nameservers if
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several are available. It has sensible handling of bad responses etc.
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