A sample DNS (Domain Name Server) setting for TTL (Time to Live) might be 86400. TTL settings are entered as seconds and the max TTL time could be entered as one day like this: 60x60x24 = 86400.
For instance, if you want to reduce the cached Ttl to 10 minutes. Use a MaxCacheTtl value of 600. You can also set a different value for the Maximum Negative cache (Cached answers of non-existent domain) set the MaxNegativeCacheTtl to 0, and the DNS Client cache will not cache Negative responses. Although, if you query the same DNS server again, if the non-existent domain may be still in its cache.
All values in these entries are in seconds.
UPDATE: My original post here mentioned a number as the “maximum TTL value” possible. This was corrected by a poster that there is in fact no such thing as a limit to the maximum TTL value. Subsequently I found this which provides more information (from Alexander Ottl at Media Professionals AG):
But there is a maximum TTL in the context of BINDs cache configuration.
To quote the document:
max-ncache-ttl
To reduce network traffic and increase performance the server store negative answers. max-ncache-ttl is used to set a maximum retention time for these answers in the server is seconds. The default max-ncache-ttl is 10800 seconds (3 hours). max-ncache-ttl cannot exceed the maximum retention time for ordinary (positive) answers (7 days) and will be silently truncated to 7 days if set to a value which is greater than 7 days.
–
Alexander Ottl
Media Professionals AG
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Tags: Alexander, Cache Configuration, Client Cache, Dns Cache, Dns Client, Dns Server, Domain Name Server, Domain Server, Exceed, Maximum Retention, Media Professionals, Negative Answers, Negative Responses, Network Traffic, Quote, Retention Time, Ttl Value
I don’t think you know what you are talking about. Please don’t give out incorrect information. The max TTL allowed is not one day. I’ve seen ones of 1 week or even 3 weeks. And you don’t want to set negative TTL to 0 because that defeats the purpose of why it was created.
Thank you for letting me know about that. I have updated the post with additional information.
Deltaray is correct in indicating that the max TTL allowed is not one day, but your correction is wrong: there is a maximum allowed TTL value.
Per RFC2181: It is hereby specified that a TTL value is an unsigned number, with a minimum value of 0, and a maximum value of 2147483647 (http://www.rfc-editor.org/rfc/rfc2181.txt)
The Wikipedia page on DNS includes the same information (http://en.wikipedia.org/wiki/D.....ce_records)