<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><br class=""></div><div class=""> I haven’t seen a IP address in a MX record in the last 5 years. In the 16 years since that was written, the email world has changed a lot. Email systems are larger, and tend to run by email professionals who know the standards. This did not happen:</div><div class=""><br class=""></div><div class=""><pre class="">It's reasonably clear what will happen to this protocol in the future.
System administrators will continue to use dotted-decimal domain names.
There will be occasional failures from other MTAs running under other
DNS caches; the MTA implementors and the DNS implementors will react by
adding support. Eventually, no matter what DNSEXT does, dotted-decimal
domain names will be a de facto standard.</pre><div class=""><br class=""></div><div class="">And the DNSEXT working group never changed the MX standard.</div></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""> Sometimes it might better to go with the Standard way of doing things. You can’t keep adding non-standard cruft to your services, and expect a smooth lifecycle.</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Tom</div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On Sep 13, 2017, at 2:03 PM, Joe Williams <<a href="mailto:williams.joe@gmail.com" class="">williams.joe@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Thanks to asking around on twitter I think we have the why, <a href="https://cr.yp.to/djbdns/namedroppers/20000220195445-21265-qmail@cr-yp-to" class="">https://cr.yp.to/djbdns/namedroppers/20000220195445-21265-qmail@cr-yp-to</a><div class=""><br class=""></div><div class=""><a href="https://twitter.com/jedisct1/status/908072827890405376" class="">https://twitter.com/jedisct1/status/908072827890405376</a><br class=""></div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Wed, Sep 13, 2017 at 1:52 PM, Joe Williams <span dir="ltr" class=""><<a href="mailto:williams.joe@gmail.com" target="_blank" class="">williams.joe@gmail.com</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" class="">Thanks for finding that Tom! </div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br class=""><div class="gmail_quote">On Wed, Sep 13, 2017 at 1:49 PM, Tom Samplonius <span dir="ltr" class=""><<a href="mailto:tom@samplonius.org" target="_blank" class="">tom@samplonius.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word" class=""><div class="">dnscache is a pretty weird. From the webpage at <a href="http://cr.yp.to/djbdns/dnscache.html" target="_blank" class="">http://cr.yp.to/djbdns/dnsc<wbr class="">ache.html</a> ...</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">“<tt class="">dnscache</tt> handles dotted-decimal domain names internally,
giving (e.g.) the domain name <tt class="">192.48.96.2</tt>
an A record of <tt class="">192.48.96.2</tt>."</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">So it looks like dnscache will return a the IP address back for any A queries for a IP address. And it looks like it returns a basically infinite ttl.</div><div class=""><br class=""></div><div class="">Why do you need this behaviour? I used to use dnscache many years ago, but dropped it when powerdns-recursor became available. I never noticed this “feature”, and never had anything break when it went away.</div><div class=""><div class="m_-2976405360267677694h5"><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Sep 13, 2017, at 1:17 PM, Joe Williams <<a href="mailto:williams.joe@gmail.com" target="_blank" class="">williams.joe@gmail.com</a>> wrote:</div><br class="m_-2976405360267677694m_1739616544222483879Apple-interchange-newline"><div class=""><div dir="ltr" class="">Thanks for the reply Tom, I wish I knew why as well. Right now I am just trying to make my unbound config backwards compatible to not break code that expects an answer for an IP address.</div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Wed, Sep 13, 2017 at 1:05 PM, Tom Samplonius <span dir="ltr" class=""><<a href="mailto:tom@samplonius.org" target="_blank" class="">tom@samplonius.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class=""><br class="">
> ;; ANSWER SECTION:<br class="">
> 10.36.129.10. 655360 IN A 10.36.129.10<br class="">
<br class="">
<br class="">
</span> Looking at this answer, I’m not sure why anyone would want this behaviour?<br class="">
<br class="">
Is dnscache trying to dampen RFC1918 A queries by doing this?<br class="">
<span class="m_-2976405360267677694m_1739616544222483879HOEnZb"><font color="#888888" class=""><br class="">
<br class="">
Tom</font></span></blockquote></div><br class=""></div>
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