wikipedia.org DNS Report

Health Score: 79%

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Checked: 1 week before

Parent

NS records at parent servers 

ns2.wikimedia.org [ 91.198.174.239 ]
ns0.wikimedia.org [ 208.80.154.238 ]
ns1.wikimedia.org [ 208.80.153.231 ]
[These were obtained from d0.org.afilias-nst.org.]

Glue at parent nameservers 7/7

SUCCESS Parent nameservers know A records for your domain, Very good !

NS

Mismatched glue 0/7

The glue provided by the root servers does not match glue that provided by your authoritative DNS servers. 
(ns0.wikimedia.org.	86400	IN	A	208.80.154.238) present at Parent, missing at (91.198.174.239, 208.80.154.238, 208.80.153.231)
(ns1.wikimedia.org.	86400	IN	A	208.80.153.231) present at Parent, missing at (91.198.174.239, 208.80.154.238, 208.80.153.231)
(ns2.wikimedia.org.	86400	IN	A	91.198.174.239) present at Parent, missing at (91.198.174.239, 208.80.154.238, 208.80.153.231)

Nameservers A records 0/7

Some servers does not provide A records for nameservers. 
missing A record(s) for (ns0.wikimedia.org,ns1.wikimedia.org,ns2.wikimedia.org) at nameserver 91.198.174.239
missing A record(s) for (ns0.wikimedia.org,ns1.wikimedia.org,ns2.wikimedia.org) at nameserver 208.80.154.238
missing A record(s) for (ns0.wikimedia.org,ns1.wikimedia.org,ns2.wikimedia.org) at nameserver 208.80.153.231

Nameservers report identical NS records 7/7

SUCCESS The NS records at all your nameservers are identical.

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 5/5

SUCCESS You have 3 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 7/7

SUCCESS All your nameservers are also 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

SOA record

SOA record is:
Hostmaster email
hostmaster.wikimedia.org
Serial
2018092019
Refresh
43200
Retry
7200
Expire
1209600
TTL
3600

Serial agreement 0/7

DANGER Some nameservers have a different soa serial number That can occur because of recent master update (slave have not loaded master zone yet) or the is a problem in DNS.
There is serial 2018092019 at nameserver(s) (91.198.174.239)
There is serial 2018081012 at nameserver(s) (208.80.154.238 208.80.153.231)

SOA MNAME 3/3

SUCCESS SOA (Start of Authority) record states that your master (primary) name server is: ns0.wikimedia.org That server is listed at the parent servers, which is correct.

Serial value 1/1

SUCCESS SOA serial number is: 2018092019 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 : 43200 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 : 7200 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 : 3600 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 wikipedia.org
lookup wikipedia.org at A.ROOT-SERVERS.NET(198.41.0.4) 10 ms
A.ROOT-SERVERS.NET(198.41.0.4) refer to a0.org.afilias-nst.info(199.19.56.1)
lookup wikipedia.org at a0.org.afilias-nst.info(199.19.56.1) 161 ms
a0.org.afilias-nst.info(199.19.56.1) refer to ns2.wikimedia.org(91.198.174.239)
lookup wikipedia.org at ns2.wikimedia.org(91.198.174.239) 77 ms
got A record 'wikipedia.org IN A 208.80.153.224' from wikipedia.org(91.198.174.239)
Total time: 248 ms