TLD Parent Check
Good. ac2.nstld.com, the parent server I interrogated, has information for your TLD. This is a good thing as there are some other domain extensions like "co.us" for example that are missing a direct check.
Nameservers Are Listed
Good. The parent server ac2.nstld.com has your nameservers listed. This is a must if you want to be found as anyone that does not know your DNS servers will first ask the parent nameservers.
DNS Parent Sent Glue
This is bad. The parent nameserver is not sending GLUE for your nameservers.
Nameserver A Records
Good. Every nameserver listed has A records. This is a must if you want to be found..
Good. Your nameservers (the ones reported by the parent server) do not report that they allow recursive queries for anyone.
The glue records from your parent name servers do not match the glue recordsfrom your nameservers.
Glue For NS Records
INFO: GLUE was not sent when I asked your nameservers for your NS records. This is ok but you should know that in this case an extra A record lookup is required in order to get the IPs of your NS records.
Mismatched NS Records
OK. The NS records at all your nameservers are identical.
DNS Servers Responded
Good. All nameservers listed at the parent server responded.
Nameservers Are Valid
OK. All of the NS records that your nameservers report seem valid.
Good. You have multiple nameservers. According to RFC2182 section 5 you must have at least 3 nameservers, and no more than 7. Having 2 nameservers is common and ok.
Nameservers Are Lame
OK. All the nameservers listed at the parent servers answer authoritatively for your domain.
The SOA record is:
Primary nameserver: ns1.digitalocean.com
Serial #: 1547642397
NS Have Same SOA Serial
OK. All your nameservers agree that your SOA serial number is 1547642397.
SOA MNAME Entry
OK. ns1.digitalocean.com is listed at the parent servers.
Your SOA serial number is: 1547642397. The recommended format (per RFC1912 2.2) is YYYYMMDDnn, where "nn" is the revision.
Your SOA REFRESH interval is: 10800. That is OK
Your SOA RETRY value is: 3600. Looks ok
Your SOA EXPIRE value is: 604800. Looks ok
SOA Minimum TTL
Your SOA MINIMUM TTL is: 1800. Looks good
MX records reported by your nameservers:
Different MS Records At Nameservers
Oops. Some of your nameservers have different sets of MX records.
MX Name Validity
Good. I did not detect any invalid MX hostname records.
MX IPs Are Public
OK. All of your MX records appear to use public IPs.
MX A Request Returns CNAME
OK. No CNAMEs returned for A records lookups.
MX Is Not IP
OK. All of your MX records are host names.
Number Of MX Records
Oops. One or more name servers do not return multiple name servers.
Mismatched MX A Records
OK. I did not detect differing IPs for your MX records.
Duplicate MX A Records
OK. You have some duplicate MX records (MX records with the same IPs). This is not that good but if you know what you are doing than it's ok.
IP Addresses Public
OK. All of your WWW IPs appear to be public IPs.