Brian May via luv-talk wrote:
=== cut === This is the mail system at host ext-mx-out003.mykolab.com. [...] <cthum@siriustechnology.com.au>: Host or domain name not found. Name service error for name=siriustechnology.com.au type=MX: Host not found, try again === cut ===
=== cut === host -t mx siriustechnology.com.au siriustechnology.com.au mail is handled by 5 ALT2.ASPMX.L.GOOGLE.COM. siriustechnology.com.au mail is handled by 10 ALT3.ASPMX.L.GOOGLE.COM. siriustechnology.com.au mail is handled by 10 ALT4.ASPMX.L.GOOGLE.COM. siriustechnology.com.au mail is handled by 1 ASPMX.L.GOOGLE.COM. siriustechnology.com.au mail is handled by 5 ALT1.ASPMX.L.GOOGLE.COM. === cut ===
I am just curious why this might happen?
Many reasons. Can't tell which one without looking at (all) the Received headers. Note that YOUR domain, linuxpenguins.xyz, has *.mykolab.com MXs. So most LIKELY is you sent out the mail to a mykolab.com "smarthost", which had a transient DNS outage, and instead of retrying, just gave up. It never got as far as google.