[Cialug] Email server

[Nicolai]

On Sun, Apr 30, 2017 at 06:11:15AM +0000, Jared Brees wrote:

> Now that I have Mediacom with a Dynamic IP, I point
> www.relatedtotechnology.com<http://www.relatedtotechnology.comto
> geek-rtt.ddns.net.

> So, when pinging my
> www.relatedtotechnology.com<http://www.relatedtotechnology.com>, it
> auto-resolves to geek-rtt.ddns.net (as it's just a CNAME), but pinging
> the IP address gives you 127.2.3.1-client.mchsi.com.

> Not sure if the auto-resolve on CL was a result of there actually being
> a PTR record, or some other phenomenon.

The behavior you describe is a result of the implementation of your ping
program giving helpful information, not your ISP.  On OpenBSD, for
example, ping doesn't consult the DNS when doing e.g. "ping 192.0.2.8".

Similar for traceroute.  You have flags like -n and -A which control
informational/convenience functions for DNS and ASN, respectively.

Nicolai