kdschool.org DNS Report

Health Score: 76%

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Checked: 1 week before

Parent

NS records at parent servers

ns1.koreaidc.com
ns2.koreaidc.com
[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

NS

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 (220.73.163.59) there are nameservers: ns3.koreaidc.com. ns1.koreaidc.com. ns2.koreaidc.com.
At (112.175.148.241) 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:
ns3.koreaidc.com.

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

SOA record

SOA record is:
Hostmaster email
root.ns1.koreaidc.com
Serial
2016050901
Refresh
7200
Retry
1800
Expire
1209600
TTL
300

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.

SOA MNAME 3/3

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.

Info

DNS trace

Trace to kdschool.org
lookup kdschool.org at A.ROOT-SERVERS.NET(198.41.0.4) 8 ms
A.ROOT-SERVERS.NET(198.41.0.4) refer to d0.org.afilias-nst.org(199.19.57.1)
lookup kdschool.org at d0.org.afilias-nst.org(199.19.57.1) 65 ms
d0.org.afilias-nst.org(199.19.57.1) refer to ns2.koreaidc.com(unknow IP)
extra IP lookup for ns2.koreaidc.com at root server A.ROOT-SERVERS.NET(198.41.0.4)
lookup ns2.koreaidc.com at A.ROOT-SERVERS.NET(198.41.0.4) 12 ms
A.ROOT-SERVERS.NET(198.41.0.4) refer to a.gtld-servers.net(192.5.6.30)
lookup ns2.koreaidc.com at a.gtld-servers.net(192.5.6.30) 22 ms
a.gtld-servers.net(192.5.6.30) refer to ns1.koreaidc.com(220.73.163.59)
lookup ns2.koreaidc.com at ns1.koreaidc.com(220.73.163.59) 195 ms
got A record 'ns2.koreaidc.com IN A 112.175.148.241' from ns2.koreaidc.com(220.73.163.59)
lookup kdschool.org at ns2.koreaidc.com(112.175.148.241) 218 ms
got A record 'kdschool.org IN A 220.73.163.10' from kdschool.org(112.175.148.241)
Total time: 520 ms