Okay, I truly apologize in advance if what's causing my problems is a stupid misconfiguration on my part, but I'm at the end of my rope and I've been staring at this thing for so long I can't think well enough to actually work the problem. Here goes:
I'm trying to do the "Administrator" certification test. I've set up MX records before with free dns providers, so I figured this should be a piece of cake. I set everything up with my 2 buck domain from godaddy. I tried sending the email, and I got the message:No MX found for your domain. Failed to get AAAA
So, following my instincts and working the problem from the bottom up, I decided to do a test:
#>nslookup mierdinv6.info 18.104.22.168
#>nslookup mierdinv6.info ns2.he.net
*** ns2.he.net can't find mierdinv6.info: Server failed
#>nslookup mierdinv6.info ns3.he.net
*** ns3.he.net can't find mierdinv6.info: Server failed
As you can see, I resolved my domain's AAAA record correctly with google's servers. I also tried a number of other public dns servers - all came back with the correct AAAA record. However, both he.net ns servers I tried did not have any records at all.
Now I've read around these forums and it looks like the majority of folks' problems lie in either not setting the TTL to a small enough value, so that their changes don't propagate around quickly, or they don't wait long enough, or both.
I've set my TTLs to the lowest value godaddy will allow (30 mins) and I've kept everything in the same configuration for a few hours now.
From the looks of things, he.net's ns servers just can't resolve the domain. But that's weird because everyone else can.