Test Question Verification

  • Thread starter Thread starter Kerry Wilson
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Kerry Wilson

I just took a test and missed two questions...I know why I missed the first
one, but this one I definitely blanked on.



A server named Server #1 is located in the main office and hosts the primary
zone for XYZ.com. The 10 other servers are located in branch offices. These
10 servers host secondary zones for XYZ.com.

The network connections between the main office and the branch offices
fails. You need to ensure that a zone transfer takes place as soon as the
network connections between the main office and the branch offices become
available. You also need to make sure that network traffic does not
increase. What should you do on Server #1?



A. Change the Time to Live (TTL) for the SOA record to 1 minute.

B. Change the retry interval to 1 minute.

C. Change the serial number to 1558.

D. Change the serial number to 1556



Can someone please tell me the answer here and why? Even when I go through
the docs I can not "comprehend" the correct answer. Thanks.
 
Kerry Wilson said:
I just took a test and missed two questions...I know why I missed the first
one, but this one I definitely blanked on.



A server named Server #1 is located in the main office and hosts the
primary zone for XYZ.com. The 10 other servers are located in branch
offices. These 10 servers host secondary zones for XYZ.com.

The network connections between the main office and the branch offices
fails. You need to ensure that a zone transfer takes place as soon as the
network connections between the main office and the branch offices become
available. You also need to make sure that network traffic does not
increase. What should you do on Server #1?



A. Change the Time to Live (TTL) for the SOA record to 1 minute.

B. Change the retry interval to 1 minute.

C. Change the serial number to 1558.

D. Change the serial number to 1556



Can someone please tell me the answer here and why? Even when I go
through the docs I can not "comprehend" the correct answer. Thanks.
Click to expand...

Without putting too much thought into it seems you'd increase the serial
number on the primary zone to ensure that the secondary servers know they
have an update waiting. However I'm not sure there is enough information as
they never gave us a number in the question. If you change the TTL they
will update, but that will generate more traffic in the long run of the
network. I'm not sure what the retry interval is without goodling.

What did they say the anwer was?

HTH.

Matt
MCT, MCSE
 
Kerry Wilson said:
I just took a test and missed two questions...I know why I missed the first
one, but this one I definitely blanked on.



A server named Server #1 is located in the main office and hosts the
primary zone for XYZ.com. The 10 other servers are located in branch
offices. These 10 servers host secondary zones for XYZ.com.

The network connections between the main office and the branch offices
fails. You need to ensure that a zone transfer takes place as soon as the
network connections between the main office and the branch offices become
available. You also need to make sure that network traffic does not
increase. What should you do on Server #1?



A. Change the Time to Live (TTL) for the SOA record to 1 minute.

B. Change the retry interval to 1 minute.
Click to expand...
Google says it checks every 2 minutes by default... changing to one minute
would speed it up - this might be the best answer but I want more info to be
sure.

http://support.microsoft.com/kb/323592
C. Change the serial number to 1558.

D. Change the serial number to 1556



Can someone please tell me the answer here and why? Even when I go
through the docs I can not "comprehend" the correct answer. Thanks.
Click to expand...
Matt
 
Kerry Wilson said:
The answer was C: - which I defintely do not know! Any idea there?
Click to expand...
You understand that it uses the serial number to know if it needs an update
or not right?

Matt
 
Yes I know the concept of serial numbers being used for identifying any
changes required. I just did not know from this practive test I took since
it did not have the details I expected...that's just me though.
 
The 2 minute interval regardless of retry value configured on SOA was a
known issue fixed by a patch (a bug, so to speak), and would as such not be
included in a test question. Default value on SOA is 15 min.

TTL to one minute affects caching of resolved queries and would result in
more query traffic on the network.

Bumping serial number up by 1 digit on the primary would trick secondaries
into thinking a newer copy of the zone was available, and cause them to
replicate. But if a newer copy already existed and hadnt been replicated due
to network connectivity, than this would be irrelevant as the serial should
already be higher on the primary.

Setting retry interval to 1 minute would cause secondaries to retry more
quickly, and therefore succeed in pulling an updated copy more quickly, but
would not increase network traffic under normal conditions, making this the
best answer in my opinion.
 
Pete Zerger said:
The 2 minute interval regardless of retry value configured on SOA was a
known issue fixed by a patch (a bug, so to speak), and would as such not
be included in a test question. Default value on SOA is 15 min.
Click to expand...
Yeah, that was on the Q article I cited.
TTL to one minute affects caching of resolved queries and would result in
more query traffic on the network.
Click to expand...

Yeah, I also said this.
Bumping serial number up by 1 digit on the primary would trick secondaries
into thinking a newer copy of the zone was available, and cause them to
replicate. But if a newer copy already existed and hadnt been replicated
due to network connectivity, than this would be irrelevant as the serial
should already be higher on the primary.
Click to expand...

Echo in here? The issue was they didn't give the initial serial number so i
coudln't be sure that was correct.
 
Bumping serial number up by 1 digit on the primary would trick secondaries
into thinking a newer copy of the zone was available, and cause them to
replicate. But if a newer copy already existed and hadnt been replicated due
to network connectivity, than this would be irrelevant as the serial should
already be higher on the primary.
Click to expand...
I'm with you most of the way, Pete, but I'm not sure about this. If
the primary is higher, then the secondaries will assume that zone
transfer is required. When zone transfer has completed the serial
(sequence) numbers will be the same.

So there are two cases if the sequence number stays the same:

a) The primary has been updated while the secondaries were out of
contact, in which case the serial number will have been increased
anyway, and zone transfer will occur, and the secondaries will end up
with the same serial number.

b) The primary has not updated, and therefore the secondaries when
they can connect will not zone transfer, since the serial numbers will
be the same.

If you raise the sequence number at the primary, this forces the first
case and zone transfer will *always* occur, increasing the traffic.

At least, that's how I thought it worked.

Cheers,

Cliff
 
Sorry, thought you were still confused. Just giving you best answer and
clear justification for ruling the others out.
 
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