On Wed, May 16, 2012 at 6:04 AM, Richard McClary <[email protected]> wrote: > I was “distracted” by the presence of the trailing dots rather than the > absence of anything meaningful (like a domain name) prior to the dot.
The two things are related. When it comes to a DNS server, unqualified names typically get the origin appended. Consider: $ORIGIN aspca.org. faxcore1.mwro.aspca.org. A 63.85.204.151 faxcore1.mwro.aspca.org A 63.85.204.151 The above describes two different domains. They second record will be qualified with the origin. The computer thus ends up using: faxcore1.mwro.aspca.org. A 63.85.204.151 faxcore1.mwro.aspca.org.aspca.org. A 63.85.204.151 While technically valid, it's not very useful. :) This behavior exists so one can do things like this: $ORIGIN aspca.org. www A 184.106.10.179 webmail A 65.206.80.44 $ORIGIN mwro.aspca.org. faxcore1 A 63.85.204.151 foo A 192.0.2.37 As shorthand for: www.aspca.org. A 184.106.10.179 webmail.aspca.org. A 65.206.80.44 faxcore1.mwro.aspca.org. A 63.85.204.151 foo.mwro.aspca.org. A 192.0.2.37 > SO, the original MX, “faxcore1.mwro.”, did nothing (but it did not get in > the way or otherwise break things). Correct. > Adding another one ... pointing to another address also did nothing… Correct. > MX record now says “faxcore1.mwro.aspca.org. MX 20 > faxcore2.mwro.aspca.org.” Looks good as far as DNS is concerned. Without knowing anything about < faxcore2.mwro.aspca.org.>, I can't comment on whether it will do anything sensible. :) > The record “faxcore1.mwro.aspca.org. MX > 10 faxcore1.mwro.aspca.org.”, Cogent tells me, is redundant and won’t be > created. That's broken. $ *dig +noall +nocl +nottl +ans ANY faxcore1.mwro.aspca.org. * faxcore1.mwro.aspca.org. A 63.85.204.151 faxcore1.mwro.aspca.org. MX 20 faxcore2.mwro.aspca.org. $ The above says two things: 1. <faxcore1.mwro.aspca.org.> is a host with IP address <63.85.204.151>. 2. Mail for <faxcore1.mwro.aspca.org.> is handled by < faxcore2.mwro.aspca.org.> at all times. Note the complete absence of telling mail to go to < faxcore1.mwro.aspca.org.> at any point. You really need to start looking at what these records mean. DNS tells the computer what to do. If you don't understand what you're telling the computer to do, you're going to have trouble. -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
