[dns-operations] TTL=0

Andrew Sullivan ajs at anvilwalrusden.com
Fri Jan 18 23:55:02 UTC 2019

Seems to me RFC2181 already answered this years ago.
Andrew Sullivan
Please excuse my clumbsy thums.

On January 18, 2019 17:21:40 Greg Choules <gregchoules at googlemail.com> wrote:
> Hi Fred.
> No, I am not talking about dscacheutil or any particular client software. I 
> just want to know whether, in the opinion of the world's DNS professionals, 
> recursive servers should or shouldn't ever send answers from cache with TTL=0.
> cheers, Greg
> On Thu, 17 Jan 2019 at 23:15, m3047 <m3047 at m3047.net> wrote:
> Who cares about the RFC? In practice, SOME caching resolvers (and that's
> being charitable) WILL answer with TTL=0. I've had to live with PFSense
> deployments which did this.
> Which in turn leads to things like (for Mac users):
> dscacheutil -flushcache
> Is that what you're talking about?
> On Thu, 17 Jan 2019, Greg Choules wrote:
>> [...]
>> Is there ever a case, for cached answers, that the recursive server would
>> answer the client with TTL=0? Or would that be illegal? RFC1034 states that
>> records with TTL=0 "should not be cached". Note "should" and not "must".
> _______________________________________________
> dns-operations mailing list
> dns-operations at lists.dns-oarc.net
> https://lists.dns-oarc.net/mailman/listinfo/dns-operations
> dns-operations mailing list
> https://lists.dns-oarc.net/mailman/listinfo/dns-operations

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.dns-oarc.net/pipermail/dns-operations/attachments/20190118/1a95304b/attachment.html>

More information about the dns-operations mailing list