HOTSPOT
Your network contains a DNS server named Server1 that runs Windows Server 2012 R2.
Server1 has a zone namedcontoso.com. The network contains a server named Server2 that
runs Windows Server 2008 R2. Server1 and Server2 are members ofan Active Directory
domain named contoso.com.
You change the IP address of Server2.
Several hours later, some users report that they cannot connect to Server2.
On the affected users’ client computers, you flush the DNS client resolver cache, and the
users successfully connect to Server2.
You need to reduce the amount of time that the client computers cache DNS records from contoso.com.
Which value should you modify in the Start of Authority (SOA) record?To answer, select the
appropriate setting in the answer area.
Answer: 
Explanation:
The Default TTL, is just that a default for newly created records. Once the records are
created their TTL is independent of the Default TTL on the SO
A) Microsoft DNS implementation copies the Default TTL setting to all newly created records
their by giving them all independent TTL settings.
SOA Minimum Field: The SOA minimum field has been overloaded in the past to have three
different meanings, the minimum TTL value of all RRs in a zone, the default TTL of RRs
which did not contain a TTL value and the TTL of negative responses.
Despite being the original defined meaning, the first of these, the minimum TTL value of all
RRs in a zone, has never in practice been used and is hereby deprecated. The second, the
default TTL of RRs which contain no explicit TTL in the master zone file, is relevant only at
the primary server. After a zone transfer all RRs have explicit TTLs and it is impossible to
determine whether the TTL for a record was explicitly set or derived from the default after a
zone transfer. Where a server does not require RRs to include the TTL value explicitly, it
should provide a mechanism, not being the value of the MINIMUM field of the SOA record,
from which the missing TTL values are obtained. How this is done is implementation
dependent.
TTLs also occur in the Domain Name System (DNS), where they are set by an authoritative
name server for a particular resource record. When a caching (recursive) nameserver
queries the authoritative nameserver for a resource record, it will cache that record for the
time (in seconds) specified by the TTL. If a stub resolver queries the caching nameserver for
the same record before the TTL has expired, the caching server will simply reply with the
already cached resource record rather than retrieve it from the authoritative nameserver
again.
Shorter TTLs can cause heavier loads on an authoritative nameserver, but can be useful
when changing the address of critical services like Web servers or MX records, and
therefore are often lowered by the DNS administrator prior to a service being moved, in
order to minimize disruptions.
http: //support. microsoft. com/kb/297510/en-us
http: //support. microsoft. com/kb/297510/en-us
https: //en. wikipedia. org/wiki/Time_to_live
http: //www. faqs. org/rfcs/rfc2308. html#ixzz0qVpTEitk
I disagree with this answer…
The explanation states that once the record has been created, it has an independant TTL. In other words, changing the Default TTL will only affect records that are created AFTER this change has been made. Pre-existing records will be unaffected.
Due to this,and the fact the question states “reduce the amount of time that the client computers cache DNS records for CONTOSO.COM”, I would suggest that the answer should be…
TTL for this record:
Anybody have any thoughts on this?
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and this one…
http://www.hpdumps.com/official-2014-latest-microsoft-70-410-exam-dump-free-download51-60-2-2-2-2-2-2.html
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The SOA in the example provides TTL values for new records created in the zone. Minimum TTL value dictates how long the server\client should hold the record in cache (See TechNet article CC816941) before requesting the DNS record again. Indeed pre-existing records will be unaffected by this change but is the best you can do from the window presented.
The “TTL for this record” option is TTL for the SOA resource record not individual records for the zone. Again same TechNet reference as above.
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Gareth, careful with answers on these websites. Question 3 on that site is totally wrong, Delegation is for child domains and not delegation like we use in ADUC. So I would not rely on the answer for the question we are discussing here. Regards
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You are wordy. You wrote too much but useless.
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“Minimum TTL” is correct.
Explanation is here:
https://social.technet.microsoft.com/Forums/windowsserver/en-US/b32762bc-cf39-4c58-9344-b3b09c85c22e/ttl-value-for-a-zone-record-does-not-propagate-to-other-dns-server?forum=winserverNIS
Conclusion:
– The “Minimum (default) TTL:” setting will replicate to all DC/DNS servers that are in the same replication scope as the zone and will also dictate the value for the “TTL for this record” setting.
– The “TTL for this record” setting will not replicate and is server specific where set, but with AD integrated zones, it will take on the value from “Minimum (default) TTL:” setting that gets replicated.
– If you want the “TTL for this record” to be replicated, you have to choose one DC, then changed the “Minimum (default) TTL:” setting to whatever you want the “TTL for this record” to be, allow it to replicate, then change the “TTL for this record” on the DC that you changed the “Minimum (default) TTL:” setting.
Written by:
Ace Fekay
MVP, MCT, MCITP/EA, MCTS Windows 2008/R2 & Exchange 2007, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP – Directory Services
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I would say it depends on the exact wording of the question:
If they want you to reduce the time computers cache DNS records for contoso.com then I would choose to reduce the minimum default TTL, if they only want you to get this specific record out of the computers cache then I just would reduce the records TTL.
Hope the actual question in the exam makes this clearer!
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It is pretty clear, explains the problem you had and how it was resolved (clearing client DNS cache). Second distinct block of text then states what you need to do.
How do you reduce the time clients cache DNS records for this zone. Which value do you change?
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You need to reduce the amount of time that the client computers cache DNS records from contoso.com.
That’s the question. All future records. Hopefully the real question is clear.
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the 100% sure ans is TTL FOR THIS RECORD.
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That’s 100% wrong.
The TTL for the SOA is merely how long the SOA record is cached on clients. The SOA is Server1, the IP problem happened with Server2.
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You dont read.
“You need to reduce the amount of time that the client computers cache DNS records from contoso.com.”
There is nothing about server2…
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it should be minimum ttl
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It’s “Minimum TTL”, which defines the default TTL for all records in the zone.
In Microsoft DNS, all records are created with the TTL defined in the SOA (zone properties in DNS) unless you manually change a record to a longer (or shorter) TTL value on the record itself. The problem with this question is that the TTL is created on the record already, and it won’t shorten the TTL for existing records. Not sure how it would help…
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i think the best way to solve this is to enable the Advanced View via View > Advanced in the DNS MMC and change the TTL on the individual DNS record, in this case for server2..
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