RE: [NTISP] question on the DNS method

Madscientist ( (no email) )
Fri, 21 Apr 2000 17:40:22 -0400

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Would it not also be wise to put a router between the two networks and
advertise the alternate routing through BGP? Then you would have fault
tolerance in connectivity as well as DNS.

For my $0.02, I believe that the root servers only provide the addresses of
your registered DNS servers (all of them)Ö then the resolving agent
presumably queries the first DNS server, or failing that (time out or no
connection) will query the secondary server(s) that were returned in the
original query.

Of course, thereís a good chance that the query never gets to the root
servers anyway because it would likely be answered by one of the subordinate
DNS servers in the chain before the roots had to get involved.

Iím pretty sure that the root DNS servers do not resolve anything but other
DNS servers.

Hope this helps,
_Pete

-----Original Message-----
From: ntisp-request@iea-software.com
[mailto:ntisp-request@iea-software.com]On Behalf Of David Payer
Sent: Friday, April 21, 2000 5:21 PM
To: ntisp@iea-software.com
Subject: [NTISP] question on the DNS method

Today our upstream had an outage and nothing was available from our network.
Interestingly, we had just installed another circuit but DNS does not point
to any server on that network.

I am not sure of the methodology of the root servers.

If a nameserver looks up the authoritative name server for a zone and that
nameserver is unavailable, does it simply timeout for a period and then
search for a secondary server or does it immediately look for secondary name
servers?

I'd appreciate any comments. I am considering putting my secondary on my
other network but I want to understand the process before I do that.

David Payer
OMNI Internet

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<div class=3DSection1>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'>Would it not
also be wise to put a router between the two networks and advertise the
alternate routing through BGP? Then you would have fault tolerance in
connectivity as well as DNS.<o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'><![if =
!supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span style=3D'font-size:12.0pt;font-family:Verdana'>For =
my $0.02, I
believe that the root servers only provide the addresses of your =
registered DNS
servers (all of them)&#8230; then the resolving agent presumably queries =
the first DNS
server, or failing that (time out or no connection) will query the =
secondary
server(s) that were returned in the original =
query.<o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'><![if =
!supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span style=3D'font-size:12.0pt;font-family:Verdana'>Of =
course,
there&#8217;s a good chance that the query never gets to the root =
servers anyway
because it would likely be answered by one of the subordinate DNS =
servers in
the chain before the roots had to get =
involved.<o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'><![if =
!supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'>I&#8217;m pretty sure
that the root DNS servers do not resolve anything but other DNS =
servers.<o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'><![if =
!supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span style=3D'font-size:12.0pt;font-family:Verdana'>Hope =
this
helps,<o:p></o:p></span></font></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'>_Pete<o:p></o:p></span></f=
ont></span></p>

<p class=3DMsoNormal><span class=3DEmailStyle15><font size=3D3 =
color=3Dnavy
face=3DVerdana><span =
style=3D'font-size:12.0pt;font-family:Verdana'><![if =
!supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></span></font></span></p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DTahoma><span =
style=3D'font-size:10.0pt;font-family:Tahoma;color:black'>-----Original
Message-----<br>
<b><span style=3D'font-weight:bold'>From:</span></b>
ntisp-request@iea-software.com =
[mailto:ntisp-request@iea-software.com]<b><span
style=3D'font-weight:bold'>On Behalf Of </span></b>David Payer<br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Friday, April 21, =
2000 5:21
PM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> =
ntisp@iea-software.com<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> [NTISP] question =
on the
DNS method</span></font></p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
face=3D"Times New Roman"><span
style=3D'font-size:12.0pt'><![if =
!supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></span></font></p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;color:black'>Today
our upstream had an outage and nothing was available from our network.
Interestingly, we had just installed another circuit but DNS does not =
point to
any server on that network.</span></font><font color=3Dblack><span
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
color=3Dblack
face=3D"Times New Roman"><span =
style=3D'font-size:12.0pt;color:black'>&nbsp;</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;color:black'>I am
not sure of the methodology of the root servers.</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
color=3Dblack
face=3D"Times New Roman"><span =
style=3D'font-size:12.0pt;color:black'>&nbsp;</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;color:black'>If a
nameserver looks up the authoritative name server for a zone and that
nameserver is unavailable, does it simply timeout for a period and then =
search
for a secondary server or does it immediately look for secondary name =
servers?</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
color=3Dblack
face=3D"Times New Roman"><span =
style=3D'font-size:12.0pt;color:black'>&nbsp;</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;color:black'>I'd
appreciate any comments. I am considering putting my secondary on my =
other
network but I want to understand the process before I do =
that.</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
color=3Dblack
face=3D"Times New Roman"><span =
style=3D'font-size:12.0pt;color:black'>&nbsp;</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;color:black'>David
Payer</span></font><font color=3Dblack><span =
style=3D'color:black;mso-color-alt:
windowtext'><o:p></o:p></span></font></p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
color=3Dblack
face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;color:black'>OMNI
Internet</span></font><font color=3Dblack><span =
style=3D'color:black;mso-color-alt:
windowtext'><o:p></o:p></span></font></p>

<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
color=3Dblack
face=3D"Times New Roman"><span =
style=3D'font-size:12.0pt;color:black'>&nbsp;</span></font><font
color=3Dblack><span =
style=3D'color:black;mso-color-alt:windowtext'><o:p></o:p></span></font><=
/p>

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