kdschool.org DNS Report

Health Score: 76%

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Checked: 2 months before


NS records at parent servers

[These were obtained from d0.org.afilias-nst.org.]

Glue at parent nameservers 0/7

WARNING The parent servers are not providing glue for all your nameservers. This means that they are supplying the NS records (host.example.com), but not supplying the A records. That may cause some extra milliseconds in DNS. This will usually occur if your DNS servers are not in the same TLD as your domain


Mismatched glue 7/7

Skip glue checking. Make sure the nameservers domain is good standing Check koreaidc.com

Nameservers A records 7/7

SUCCESS Nameservers do include corresponding A records when asked for your NS records. This ensures that your DNS servers know the A records corresponding to all your NS records.

Nameservers report identical NS records 0/7

The NS records at your nameservers are different
At ( there are nameservers: ns3.koreaidc.com. ns1.koreaidc.com. ns2.koreaidc.com.
At ( there are nameservers: ns2.koreaidc.com. ns3.koreaidc.com.

Nameservers respond 10/10

SUCCESS All of your nameservers listed at the parent nameservers responded.

Nameserver name validity 7/7

SUCCESS All of the NS records that your nameservers report are valid (no IPs or partial domain names).

Number of nameservers 2/5

WARNING You have 2 nameservers. You must have at least 2 nameservers (RFC2182 section 5 recommends at least 3 nameservers), and preferably no more than 7.

Lame nameservers 7/7

SUCCESS All the nameservers listed at the parent servers answer authoritatively for your domain.

Missing (stealth) nameservers 0/7

DANGER There are nameservers not listed at the parent servers:

Root missing nameservers 7/7

SUCCESS All of the nameservers listed at the parent nameservers are also listed as NS records at your nameservers.

Nameservers on separate class C's 7/7

SUCCESS Nameservers are in a different networks.

public IPs 7/7

SUCCESS All of your NS records appear to use public IPs.


SOA record

SOA record is:
Hostmaster email

Serial agreement 7/7

SUCCESS All your nameservers agree that your SOA serial number is 2016050901 That means that all your nameservers are using the same data.


SUCCESS SOA (Start of Authority) record states that your master (primary) name server is: ns1.koreaidc.com That server is listed at the parent servers, which is correct.

Serial value 1/1

SUCCESS SOA serial number is: 2016050901 This appears to be in the recommended format of YYYYMMDDnn, where 'nn' is the revision. This number must be incremented every time you make a DNS change.

Refresh value 1/1

SUCCESS SOA Retry interval is : 7200 seconds. This seems OK. (Values about 3600-7200 seconds is good if not using DNS NOTIFY; RFC1912 2.2 recommends a value between 1200 to 43200 seconds (20 minutes to 12 hours)). This value determines how often secondary/slave nameservers check with the master for updates.

Retry value 1/1

SUCCESS SOA Retry interval is : 1800 seconds. This seems OK. (Values about 120-7200 seconds is good). The retry value is the amount of time your secondary/slave nameservers will wait to contact the master nameserver again if the last attempt failed.

Expire value 1/1

SUCCESS SOA Expire time is : 1209600 seconds. This seems OK. (Values 604800 to 2419200 seconds (1-4 weeks) is good). RFC1912 suggests 2-4 weeks. This is how long a secondary/slave nameserver will wait before considering its DNS data stale if it can't reach the primary nameserver.

TTL value 1/1

SUCCESS SOA Expire time is : 300 seconds. This seems OK. (about 300 to 86400 seconds or 5 min - 24 hours is good). RFC2308 suggests a value of 1-3 hours. This value used to determine the default (technically, minimum) TTL (time-to-live) for DNS entries, but now is used for negative caching.


DNS trace

Trace to kdschool.org
lookup kdschool.org at A.ROOT-SERVERS.NET( 8 ms
A.ROOT-SERVERS.NET( refer to d0.org.afilias-nst.org(
lookup kdschool.org at d0.org.afilias-nst.org( 65 ms
d0.org.afilias-nst.org( refer to ns2.koreaidc.com(unknow IP)
extra IP lookup for ns2.koreaidc.com at root server A.ROOT-SERVERS.NET(
lookup ns2.koreaidc.com at A.ROOT-SERVERS.NET( 12 ms
A.ROOT-SERVERS.NET( refer to a.gtld-servers.net(
lookup ns2.koreaidc.com at a.gtld-servers.net( 22 ms
a.gtld-servers.net( refer to ns1.koreaidc.com(
lookup ns2.koreaidc.com at ns1.koreaidc.com( 195 ms
got A record 'ns2.koreaidc.com IN A' from ns2.koreaidc.com(
lookup kdschool.org at ns2.koreaidc.com( 218 ms
got A record 'kdschool.org IN A' from kdschool.org(
Total time: 520 ms