f697b33283
* plugins: Return error for multiple use of some Return plugin.ErrOnce when a plugin that doesn't support it, is called mutliple times. This now adds it for: cache, dnssec, errors, forward, hosts, nsid. And changes it slightly in kubernetes, pprof, reload, root. * more tests
57 lines
1.1 KiB
Markdown
57 lines
1.1 KiB
Markdown
# nsid
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## Name
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*nsid* - adds an identifier of this server to each reply.
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## Description
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This plugin implements [RFC 5001](https://tools.ietf.org/html/rfc5001) and adds an EDNS0 OPT
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resource record to replies that uniquely identify the server. This is useful in anycast setups to
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see which server was responsible for generating the reply and for debugging.
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This plugin can only be used once per Server Block.
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## Syntax
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~~~ txt
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nsid [DATA]
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~~~
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**DATA** is the string to use in the nsid record.
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If **DATA** is not given, the host's name is used.
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## Examples
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Enable nsid:
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~~~ corefile
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. {
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whoami
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nsid Use The Force
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}
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~~~
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And now a client with NSID support will see an OPT record with the NSID option:
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~~~ sh
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% dig +nsid @localhost a whoami.example.org
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;; Got answer:
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;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46880
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;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 3
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....
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; OPT PSEUDOSECTION:
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; EDNS: version: 0, flags:; udp: 4096
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; NSID: 55 73 65 20 54 68 65 20 46 6f 72 63 65 ("Use The Force")
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;; QUESTION SECTION:
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;whoami.example.org. IN A
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~~~
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## Also See
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[RFC 5001](https://tools.ietf.org/html/rfc5001)
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