Resource: Windows 2000 Server Resource kit TCP/IP Core Networking Guide  

DNS > Aging and Scavenging of Stale Records

Aging and Scavenging of Stale Records
 

در Dynamic update شما ركوردهاي را بصورت خودكار در Zone هاي DNS ايجاد مي كنيد امكان دارد سيستمي كه اين ركورد را در Zone ايجاد كرده نتواند

بدرستي آن را بعد از پايان زمان TTL در DNS پاك كند اين مشكل ممكن هست در شبكه رخ دهد . واين موجب باقي ماندن اين ركورد هاي بي ارزش در DNS
مي شود . به اين ركوردهاي Stale Record گفته مي شود . منظور A , PTR Resource Record  مي باشد .
وجود اين ركوردهاي بي ارزش اولا موجب گرفتن فضايي در DNS مي شوند .دوم اينكه DNS براي جواب دادن به هر query از اين ركوردها نيز استفاده مي كند كه
اين خود موجب بالا رفتن بار كاري و پايين آمدن سرعت جواب دهي DNS به Client ها مي شود .

  Dnscmd.exe

Aging and Scavenging Parameters
در جدول زير مي توان Parameter هاي موجود در Zone ها را و چگونگي كار آنها را مشاهده كرد .

Table 6.9 Aging and Scavenging Parameters for Zones

Zone Parameter Description Configuration Tool Notes
No-refresh interval Time during which the server does not accept refreshes for the record. (The server still accepts updates.)

This value is the interval between the last time a record was refreshed and the earliest moment it can be refreshed again.

DNS console and Dnscmd.exe When an Active Directory–integrated zone is created, this parameter is set to the DNS server parameter Default no-refresh interval.

This parameter replicates through Active Directory replication.

Refresh interval The refresh interval comes after the no-refresh interval. At the beginning of the refresh interval, the server begins accepting refreshes. After the refresh interval expires, the DNS server can scavenge records that have not been refreshed during or after the refresh interval. DNS console and Dnscmd.exe When an Active Directory–integrated zone is created, this parameter is set to the DNS server parameter Default refresh interval.

This parameter is replicated by Active Directory.

Enable Scavenging This flag indicates whether aging and scavenging is enabled for the records in the zone. DNS console and Dnscmd.exe When an Active Directory–integrated zone is created, this parameter is set to the DNS server parameter Default enable scavenging.

This parameter is replicated by Active Directory.

ScavengingServers This parameter determines which servers can scavenge records in this zone. Only Dnscmd.exe This parameter is replicated by Active Directory.
Start scavenging This parameter determines when a server can start scavenging of this zone. Not configurable This parameter is not replicated by Active Directory.
 

در جدول زير پارامترهاي سرور در زمان راه اندازي Aging AND Scavenging را مشاهده مي كنيد .

Table 6.10 Aging and Scavenging Parameters for Servers

Server Parameter Description Configuration Tool Notes
Default no-refresh interval This value specifies the no-refresh interval that is used by default for the Active Directory–integrated zone. DNS console (shown as No-refresh interval) and Dnscmd.exe By default, this is 7 days.
Default refresh interval This value specifies the refresh interval that is used by default for the Active Directory–integrated zone. DNS console (shown as Refresh interval) and Dnscmd.exe By default, this is 7 days.
Default Enable Scavenging This value specifies the Enable Scavenging parameter that is used by default for the Active Directory–integrated zone. DNS console (shown as Enable scavenging)and Dnscmd.exe By default, scavenging is disabled.
Enable scavenging This flag specifies whether the DNS server can perform scavenging of stale records. If scavenging is enabled on a server, it automatically repeats scavenging as often as specified in the Scavenging Period parameter. DNS console, Advanced View (shown as Enable automatic scavenging of stale records) and Dnscmd.exe By default, scavenging is disabled.
Scavenging Period This period specifies how often a DNS server enabled for scavenging can remove stale records. DNS console, Advanced View (shown as Scavenging Period) and Dnscmd.exe By default, this is 7 days.
Configuring Scavenging Parameters
اما براي راه اندازي يا در واقع پاك سازي سرور يا Zone هاي DNS از اين ركورد ها بايد مراحل زير را انجام داد .لازم بذكر مي باشد كه اين عمل را مي توان در
مدت زمان مشخص بصورت دوره اي انجام داد كه Default اين زمان 7 روز مي باشد .

براي اين كار شما بر روي Zone در DNS Console بايد Right Click كنيد و Properties را انتخاب كنيد و در Tab General گزينه Aging را انتخاب

كنيد

  

پس از انتخاب اين گزينه منوي زير باز مي شود و شما بايد مدت زمان مورد نظر خود را تعريف كنيد.

  

Scavenge stale resource records

اين گزينه  بايد فعال شود تا در مدت زمان تعريف شده سيستم ركوردهاي خراب و بي ارزش را از Zone پاك كند .

 
 

Last Updated: October 01, 2006

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DNS > Aging and Scavenging of Stale Records

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