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Checked: 1 month before
Parent
NS records at parent servers
ns.grdns.it
ns.grdns.cz [ 81.2.194.104 ]
[These were obtained from b.ns.nic.cz.]
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
0/7
The glue provided by the root servers does not match glue that provided by your authoritative DNS servers.
(ns.grdns.cz. 3600 IN A 81.2.194.104) present at Parent, missing at (95.110.254.167)
Nameservers A records
0/7
Some servers does not provide A records for nameservers.
missing A record(s) for (ns.grdns.cz,ns.grdns.it) at nameserver 95.110.254.167
Nameservers report identical NS records
7/7
SUCCESS
The NS records at all your nameservers are identical.
Nameservers respond
0/10
Some nameservers does not respond:
2001:15e8:101:1::c268
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
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
admin.grdns.cz
Serial
2020012101
Refresh
3600
Retry
1800
Expire
2592000
TTL
3600
Serial agreement
7/7
SUCCESS
All your nameservers agree that your SOA serial number is 2020012101 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: ns.grdns.cz That server is listed at the parent servers, which is correct.
Serial value
1/1
SUCCESS
SOA serial number is: 2020012101 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 : 3600 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
0/1
WARNING
SOA Expire time is : 2592000 seconds. This seems too big;. (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 hnizdil-kola.cz
lookup hnizdil-kola.cz at A.ROOT-SERVERS.NET(198.41.0.4) 4 ms
A.ROOT-SERVERS.NET(198.41.0.4) refer to a.ns.nic.cz(194.0.12.1)
lookup hnizdil-kola.cz at a.ns.nic.cz(194.0.12.1) 33 ms
a.ns.nic.cz(194.0.12.1) refer to ns.grdns.cz(81.2.194.104)
lookup hnizdil-kola.cz at ns.grdns.cz(81.2.194.104) 31 ms
got A record 'hnizdil-kola.cz IN A 81.91.84.51' from hnizdil-kola.cz(81.2.194.104)