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73e408f1d0
- Cached messages that reach 0 TTL are considered expired. This prevents Unbound itself from issuing replies with TTL 0 and possibly causing a thundering herd at the last second. Upstream replies of TTL 0 still get the usual pass-through but they are not considered for caching from Unbound or any of its caching modules. - 'serve-expired-reply-ttl' is changed and is now capped by the original TTL value of the record to try and make some sense when replying with expired records. - TTL decoding was updated to adhere to RFC8767 section 4 where a set high-order bit means the value is positive instead of 0.
72 lines
1.3 KiB
Text
72 lines
1.3 KiB
Text
; This is a comment.
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; config options go here.
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server:
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serve-expired: yes
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serve-expired-client-timeout: 0
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prefetch: yes
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forward-zone: name: "." forward-addr: 216.0.0.1
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CONFIG_END
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SCENARIO_BEGIN Zero ttl answer needs to override servfail in cache.
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RANGE_BEGIN 0 100
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ENTRY_BEGIN
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MATCH opcode qtype qname
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ADJUST copy_id
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REPLY QR RD RA SERVFAIL
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SECTION QUESTION
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www.example.com. IN A
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SECTION ANSWER
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ENTRY_END
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RANGE_END
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RANGE_BEGIN 200 300
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ENTRY_BEGIN
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MATCH opcode qtype qname
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ADJUST copy_id
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REPLY QR RD RA NOERROR
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SECTION QUESTION
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www.example.com. IN A
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SECTION ANSWER
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www.example.com. 0 IN A 10.20.30.40
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ENTRY_END
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RANGE_END
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STEP 1 QUERY
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ENTRY_BEGIN
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REPLY RD
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SECTION QUESTION
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www.example.com. IN A
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ENTRY_END
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STEP 10 CHECK_ANSWER
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ENTRY_BEGIN
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MATCH all
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REPLY QR RD RA SERVFAIL
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SECTION QUESTION
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www.example.com. IN A
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SECTION ANSWER
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ENTRY_END
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; enough to expire the servfail answer in cache
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STEP 50 TIME_PASSES ELAPSE 5
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; Expired SERVFAILS are no longer served from Unbound
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; this query gets the 0ttl answer
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STEP 230 QUERY
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ENTRY_BEGIN
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REPLY RD
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SECTION QUESTION
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www.example.com. IN A
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ENTRY_END
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STEP 240 CHECK_ANSWER
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ENTRY_BEGIN
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MATCH all ttl
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REPLY QR RD RA NOERROR
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SECTION QUESTION
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www.example.com. IN A
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SECTION ANSWER
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www.example.com. 0 IN A 10.20.30.40
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ENTRY_END
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SCENARIO_END
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