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aging and scavenging

Discussion in 'Network Infrastructure' started by nicolinux, May 9, 2007.

  1. nicolinux

    nicolinux Byte Poster

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    I do not understand that.
    If, for example, the no-refresh time is set to 12 days and the refresh time to 12, and the client change is ip after 6 days ( by dhcp ), the timestamps will never be refreshed.
    So if i run the scavenging, the record will look as 24 days old it will be delete even if is just 18. ?????
    thanks to help a poor man
    Nico
     
    Certifications: mcse win2k3, mcts x4. mcitp enterprise admin
    WIP: 70-680
  2. simongrahamuk
    Honorary Member

    simongrahamuk Hmmmmmmm?

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    *BUMP*

    I'm not 100% sure what you're asking here nico, can you expand on it a little?
     
  3. nicolinux

    nicolinux Byte Poster

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    Sorry, i am very confused about this topic.
    If i set the no-refresh time to 12 and a client reregister is ip, after
    for example 4 days. the A record is updated but the timestamp no.
    So if the refresh time is set to 12 (for example) and set the automatic scavenging,that record is only 20 days old but looks like
    24, and will be delete. ?????
    What i do not understand is:
    if a pc change is ip for some reason before the end of the no-refresh time, the timestamp will not be modify. So the aging
    will not update the timestamps.
    I am so confused that is hard for me to understand myself.
    Thanks for your help.
    Nico
     
    Certifications: mcse win2k3, mcts x4. mcitp enterprise admin
    WIP: 70-680
  4. Tinus1959

    Tinus1959 Gigabyte Poster

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    Lets start with the reason for the "no-refresh" timer. The primaiary master stores a timestamp for every record in a zone. When the zone is AD integrated it will replicated changes to other DC within a few minutes, resulting in a lot of network traffic.
    So Microsoft introduced the "no-refresh" interval. When a record is refreshed and its timestamp is updated, the server will not process additional refresh events for the length of the no-refresh interval. After this no-refresh interval, the refresh interval starts. In this periode a refresh is posible.
    Stale records have to be removed and a server does this by making a scavenging pass. Records older than the no-refresh plus the refresh interval are considered to be stale.
     
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  5. nicolinux

    nicolinux Byte Poster

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    Hi Tinus,
    maybe i do not undestand is what mean "refresh".
    When a host change is ip (by dhcp) it update the A record in the dns server. So its timestamp will be zero.
    What happen if the ip change again (ex: the nic has been replaced) and the "no-refresh time" is not elapsed yet.
    For what i understand, and i think i am wrong, the scavenging will
    delete all the A and ptr record not changed after xxxxtime.
    So if my dhcp lease expire after 30 days and the aging is setting
    no-refresh time=7 days + refresh-time= 7 days, all my records will
    be deleted.
    Is it ??
    Thanks, I am sorry to waste your time
    Nico
     
    Certifications: mcse win2k3, mcts x4. mcitp enterprise admin
    WIP: 70-680
  6. Tinus1959

    Tinus1959 Gigabyte Poster

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    When the record is changed because of DHCP it wil change the record in the primairy DNS server, but the replication to other AD servers will be prosponed. This is due to the no-refresh interval.
     
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  7. nicolinux

    nicolinux Byte Poster

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    Ok is becoming closer now.
    So i can have some dns server update and some not ? I am asking that because the default "no-refresh time " is 7 days.
    Thanks
    Nico
     
    Certifications: mcse win2k3, mcts x4. mcitp enterprise admin
    WIP: 70-680
  8. Tinus1959

    Tinus1959 Gigabyte Poster

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    Not sure what you mean.
    I'll explain again.
    When you have an active directory integrated zone, the primairy server will put a timestamp on every new record. These records are replicated in a normal way to all other DC in the domain.
    If the client is restarted, it will try to get the same ip-address back from the DHCP server. If this is granted, the DHCP server will refresh only the timestamp in the primairy server. For that server the records has changed (different timestamp) but in fact is stayed the same for DNS. There is absolutely no reason at all for the other server to be bothered with this change, so the pri server pospones the extra updates to other DC during a periode of (standard) 7 days.
     
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    WIP: MCSD, MCAD, CCNA, CCNP
  9. nicolinux

    nicolinux Byte Poster

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    Revising the book for the third time, and remembering your words
    i finally understood this topic.
    Better late then never.
    Thanks again
     
    Certifications: mcse win2k3, mcts x4. mcitp enterprise admin
    WIP: 70-680
  10. Tinus1959

    Tinus1959 Gigabyte Poster

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    No problem.
     
    Certifications: See my signature
    WIP: MCSD, MCAD, CCNA, CCNP

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