Category: DNS

DNS Root Servers
article #1017, updated 2202 days ago

As of this writing, the current authoritative list, from here:

https://www.iana.org/domains/root/servers

is:

a.root-servers.net 198.41.0.4 2001:503:ba3e::2:30 VeriSign, Inc.
b.root-servers.net 192.228.79.201 2001:500:84::b University of Southern California (ISI)
c.root-servers.net 192.33.4.12 2001:500:2::c Cogent Communications
d.root-servers.net 199.7.91.13 2001:500:2d::d University of Maryland
e.root-servers.net 192.203.230.10 2001:500:a8::e NASA (Ames Research Center)
f.root-servers.net 192.5.5.241 2001:500:2f::f Internet Systems Consortium, Inc.
g.root-servers.net 192.112.36.4 2001:500:12::d0d US Department of Defense (NIC)
h.root-servers.net 198.97.190.53 2001:500:1::53 US Army (Research Lab)
i.root-servers.net 192.36.148.17 2001:7fe::53 Netnod
j.root-servers.net 192.58.128.30 2001:503:c27::2:30 VeriSign, Inc.
k.root-servers.net 193.0.14.129 2001:7fd::1 RIPE NCC
l.root-servers.net 199.7.83.42 2001:500:9f::42 ICANN
m.root-servers.net 202.12.27.33 2001:dc3::35 WIDE Project

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Installing nslookup on Linux
article #1008, updated 2263 days ago

Increasingly, nslookup is not installed by default in major Linux distros. On Arch-based and Debian-based distros, it’s in package dnsutils,

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Opt out of the Cox special DNS
article #884, updated 2638 days ago

By default, Cox will DHCP to your systems some DNS servers which behave like OpenDNS, i.e., if there is a DNS name miss, the servers will show a hit which is a Cox search page. This can confuse a lot of things. Cox has provided a way around this:

http://www.cox.com/residential/support/internet/article.cox?articleId=e14ee070-6448-11df-ccef-000000000000

for residential at least, it uses these two IPs as static DNS:

68.105.28.13
68.105.29.13

and these do appear to be noticeably faster!

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CenturyLink DNS servers
article #881, updated 2641 days ago

A great place to find them:

http://internethelp.centurylink.com/internethelp/dns-ctl.html

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DNS Root Server IPs
article #780, updated 2916 days ago

Here is the canonical source:

http://www.internic.net/zones/named.root

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'dig' command to pull up all records for a single hostname
article #597, updated 3415 days ago

To pull up a list of all DNS records for a single hostname:

dig +nocmd yourdomain.com any +multiline +noall +answer

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Web/GUI front ends for BIND
article #287, updated 4295 days ago

Here is an interesting list:

http://www.debianadmin.com/bind-dns-server-web-interfacefrontend-or-gui-tools.html

But the best may be here:

http://sourceforge.net/projects/smbind/

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SPF records for email
article #228, updated 4456 days ago

SPF records are DNS entries for entire domains, which do a whole lot to prevent spam.  They are required on the sender side, these days, for email to be successfully received by many carriers small and large, including Yahoo and Embarq and many others.  For lots of general information:

http://www.openspf.org

For more details and syntax:

http://www.openspf.org/SPF_Record_Syntax

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Add IPv6 Reverse DNS to Server 2008
article #193, updated 4548 days ago

In Server 2008, the default protocol is IPv6.  It is not recommended to disable it in any way.

Default DNS, internal and LAN-wide, is therefore also IPv6.  All you really need is an AAAA record for the forward lookup.  But in many cases reverse lookup will have been skipped at server setup, and in such a case, it can get confusing to try to set up reverse DNS.  Reverse DNS is definitely recommended, it will smoothen out the LAN in general.

It has been very difficult to find any instructions to set up reverse IPv6 DNS on Server 2008.  Howsomever, here is one.

http://www.thirdtier.net/2009/08/adding-ipv6-to-dns/

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DNS nslookup debugging
article #103, updated 4847 days ago

This one comes from the excellent David Childers.

When you start up nslookup in a command prompt, there’s a way to get some very good additional information.

C:\Documents and Settings\davidc>nslookup -d2
------------
SendRequest(), len 41
HEADER:
opcode = QUERY, id = 1, rcode = NOERROR
header flags:  query, want recursion
questions = 1,  answers = 0,  authority records = 0,  additional = 0

QUESTIONS:
3.1.16.172.in-addr.arpa, type = PTR, class = IN

------------
------------
Got answer (78 bytes):
HEADER:
opcode = QUERY, id = 1, rcode = NOERROR
header flags:  response, auth. answer, want recursion, recursion avail.
questions = 1,  answers = 1,  authority records = 0,  additional = 0

QUESTIONS:
3.1.16.172.in-addr.arpa, type = PTR, class = IN
ANSWERS:
->  3.1.16.172.in-addr.arpa
type = PTR, class = IN, dlen = 25
name = ***-***.********.local
ttl = 1200 (20 mins)

------------
Default Server:  ***-***.********.local
Address:  172.16.1.3

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As you can see, by using the command nslookup -d2, the entirety of the conversation that nslookup is having with the DNS server is displayed.

If you believe that nslookup has locked up or died, you will be able to see the timeouts occurring as it waits for response from the DNS server.

I hope that helps!

:-)

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