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| author | Christian Poessinger <christian@poessinger.com> | 2019-12-15 15:43:37 +0100 |
|---|---|---|
| committer | Christian Poessinger <christian@poessinger.com> | 2019-12-15 15:43:37 +0100 |
| commit | 5aff67893b993364cf48edbb927661315927f00d (patch) | |
| tree | 6f6cba93260075849d4091c93689d1bb07f0d473 | |
| parent | 94d4aaada6bd9345b968da336f88a6f8f0e15874 (diff) | |
| download | vyos-documentation-5aff67893b993364cf48edbb927661315927f00d.tar.gz vyos-documentation-5aff67893b993364cf48edbb927661315927f00d.zip | |
dns-forwarding: add negative-ttl option
| -rw-r--r-- | docs/services/dns-forwarding.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/docs/services/dns-forwarding.rst b/docs/services/dns-forwarding.rst index e98d7f6b..bd05395e 100644 --- a/docs/services/dns-forwarding.rst +++ b/docs/services/dns-forwarding.rst @@ -87,6 +87,14 @@ use this file to add resolvers to assigned addresses. Maximum number of DNS cache entries. 1 million per CPU core will generally suffice for most installations. +.. cfgcmd:: set service dns forwarding negative-ttl + +A query for which there is authoritatively no answer is cached to quickly deny +a record's existence later on, without putting a heavy load on the remote +server. In practice, caches can become saturated with hundreds of thousands of +hosts which are tried only once. This setting, which defaults to 3600 seconds, +puts a maximum on the amount of time negative entries are cached. + Example ======= |