avast dot com missing nameserver reported by parent

Hick-up in a DNS check scan for avast dot com:
Missing nameservers reported by parent FAIL: The following nameservers are listed at your nameservers as nameservers for your domain, but are not listed at the parent nameservers (see RFC2181 5.4.1). You need to make sure that these nameservers are working.If they are not working ok, you may have problems!
sns.avast.com

Name Servers
ns2.avast.com 75.125.29.226
pns.avast.com 91.213.143.1

See: http://who.is/nameserver/ns2.avast.com/
and http://who.is/nameserver/pns.avast.com/

Complementary Name Servers ns2.avast.com, sns.avast.com

Sample of Domains Using sns.avast.com
Domain Registrar Create Date Expire Date More Information
caro2011.org Center of Ukrainian Internet Names dba UKRNAMES (R1787-LROR) 2013-04-12 14:30:14 2014-04-12 14:30:14 DNS → http://whois.domaintools.com/caro2011.org (registered in Panama)

Just some observations I like to present here.
Anyone to comment?

Here everything seems fine: http://dnscheck.pingdom.com/?domain=avast.com&timestamp=1410296649&view=1

he oldest DNS info involved in this analysis were:
dns last checked
avast.co.jp Mon May 12 06:42:41 2014)
avast.com.ro Fri Jul 18 16:22:19 2014)
avast.co.in Thu Aug 7 15:38:24 2014)
avastpartners.com Fri Aug 8 15:56:06 2014)
avast.ua Sun Aug 10 11:45:27 2014)
avast.com.mx Sun Aug 10 20:01:34 2014)
antivir.cz Thu Aug 14 15:34:51 2014)
kostky.org Fri Aug 15 02:35:04 2014)
avast.ru Sun Aug 17 07:52:58 2014)
avast.cl Thu Aug 21 18:31:15 2014)
alwilsw.com Thu Aug 21 19:41:15 2014)
Records
Displays various information related to AS, BGP, Routes and Location.
Base Record Preference Name IP Number Reverse Routes AS Location
91.213.143.11 - 91.213.143.11 91.213.143.11 SNS.AVAST.COM 91.213.143.0/24 AVAST Software a.s. AVAST-COM AVAST Software a.s. AS197815 AVAST-AS AVAST Software a.s. Prague, Czech Republic
PTR SNS.AVAST.COM

All the information you could ever need on what other domains are using the same nameservers, mailservers and other data.
The PTR records of 91.213.143.11 (1 shown)

  1. SNS.AVAST.COM

Pointing to 91.213.143.11 (1 shown)

  1. SNS.AVAST.COM

The IP numbers of the PTR records of 91.213.143.11 (1 shown)

  1. 91.213.143.11

Using as name servers the PTR records of 91.213.143.11 (23 shown)

  1. AVAST.CL
  2. ALWILSW.COM
  3. AVAST.COM

Being the PTR records of the PTR records of 91.213.143.11 (2 shown)

  1. 11.143.213.91.IN-ADDR.ARPA
  2. 91.213.143.11

Using as name servers pointing to 91.213.143.11 (23 shown)

  1. AVAST.CL
  2. ALWILSW.COM
  3. AVAST.COM

Map
This section displays where we think the relevant servers are located. When possible we show both city and country.
Country: Czech Republic
City: Prague
Hostname: SNS.AVAST.COM
91.213.143.11
IP: 91.213.143.11
Discussion
Discussion about the specific hostname or IP.
comments powered by Disqus
Contact
Contact information for the domain.

XXXX@avast.com is dns contact for AVAST.COM
XXXXX@verisign-grs.com is dns contact for
Whois
Complete whois information on the domain, including registrar information.
Blacklists
The blacklist table displays any potential databases where the domain might be listed due to suspicious behavior or other potentially harmful activities. Please note that a listing might not be evidence of malicious activity, and is merely an indication that a blacklisting exists. For additional information, please check the relevant database, pointed out in the table.
rtsakd20140909 rtsakmarka rut927832533 rtsakmarke1 rtsakmark136 natachalittlefrenchmakeupartist.com fulemine.cn fopwc-thecenter.org orangelineint.ru relais-inet.francetelecom.com ziddu.com youizz.com appldnld.sa-dung.com.edgesuite.net.globalredir.akadns.net blogspot.co.uk gratisindo.porno.com dongtaiwang.com 122.226.102.27 rtsakdi1
status according to robtex…

polonus

Sometimes these kind of researches online is fun.
Now we have found out that one of our avast team members and founding fathers, Jindroush, is a big LEGO fan.

See: http://whois.domaintools.com/kostky.org

Even a completely different forum there for EURObricks ;D

The late f.ravia was right in his searchlores teachings. It is all out there for those that know where and how to search.

polonus