Scavenging or something else to cleanup duplicate DNS entries?

[User Name]

We have 2 Windows 2003 DNS servers and one Windows 2003 DHCP server on
our domain.
There are 3 different subnets in DHCP.

Most servers, all printers and some random Windows workstations that
fail to accept DHCP reservations have manually entered static IP
address.
Every other Windows machine (XP or Windows Server) is on DHCP with or
without reservations.

Scavenging is not enabled and we have many duplicate entries in DNS
that are causing problems with machine names resolving to incorrect
machines. So, now we cannot trust name resolution unless we verify by
doing a ping -a on the IP to make sure the reply is labeled with the
expected device. If we find a problem, we log into DNS and manually
delete the old record.

What are the best/safestest ways to automate making sure that DNS
entries are current and prevent anything current from being mistakenly
deleted from DNS?

We have heard about scavenging, but we are not sure how to set it up
to make sure it works without deleting records that it should not.

[Meinolf Weber]

Hello User,

Scavenging is one way, you can also use this one:
http://technet.microsoft.com/en-us/l.../cc787034.aspx

Best regards

Meinolf Weber
Disclaimer: This posting is provided "AS IS" with no warranties, and confers
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> We have 2 Windows 2003 DNS servers and one Windows 2003 DHCP server on
> our domain.
> There are 3 different subnets in DHCP.
> Most servers, all printers and some random Windows workstations that
> fail to accept DHCP reservations have manually entered static IP
> address.
> Every other Windows machine (XP or Windows Server) is on DHCP with or
> without reservations.
> Scavenging is not enabled and we have many duplicate entries in DNS
> that are causing problems with machine names resolving to incorrect
> machines. So, now we cannot trust name resolution unless we verify by
> doing a ping -a on the IP to make sure the reply is labeled with the
> expected device. If we find a problem, we log into DNS and manually
> delete the old record.
>
> What are the best/safestest ways to automate making sure that DNS
> entries are current and prevent anything current from being mistakenly
> deleted from DNS?
>
> We have heard about scavenging, but we are not sure how to set it up
> to make sure it works without deleting records that it should not.
>

[moncho]

User Name wrote:
> We have 2 Windows 2003 DNS servers and one Windows 2003 DHCP server on
> our domain.
> There are 3 different subnets in DHCP.
>
> Most servers, all printers and some random Windows workstations that
> fail to accept DHCP reservations have manually entered static IP
> address.
> Every other Windows machine (XP or Windows Server) is on DHCP with or
> without reservations.
>
> Scavenging is not enabled and we have many duplicate entries in DNS
> that are causing problems with machine names resolving to incorrect
> machines. So, now we cannot trust name resolution unless we verify by
> doing a ping -a on the IP to make sure the reply is labeled with the
> expected device. If we find a problem, we log into DNS and manually
> delete the old record.
>
> What are the best/safestest ways to automate making sure that DNS
> entries are current and prevent anything current from being mistakenly
> deleted from DNS?
>
> We have heard about scavenging, but we are not sure how to set it up
> to make sure it works without deleting records that it should not.

Here is another article with relation to scavenging.

http://blogs.technet.com/networking/...e-patient.aspx

moncho

[User Name]

We are short of IP addresses. So, when a laptop if off the network
for more than a couple of days, there is a good chance the unused IP
will be automatically reassigned via DHCP to another machine. There
is quite a bit of IP address turnover in 7 days. Does this mean we
should set scavenging period to shorter than the default 7 days if we
were to enable scavenging?

There is a single DHCP server, but 2 DNS servers.
Would it be a good idea to turn off the option of DHCP clients
registering themselves into DNS and letting the DHCP server
exclusively handle the DNS registrations? Wouldn't that eliminate the
source of duplicate entries into DNS and thus eliminate the need of
scavenging after the fact?

I think duplicate entries are also occuring when laptops are carried
to different floors and meeting rooms where they may be assigned new
IP addresses in different subnets as it moves around the building even
within the same day. Will scavenging do anything about these
duplicate entries?

[moncho]

User Name wrote:
> We are short of IP addresses. So, when a laptop if off the network
> for more than a couple of days, there is a good chance the unused IP
> will be automatically reassigned via DHCP to another machine. There
> is quite a bit of IP address turnover in 7 days. Does this mean we
> should set scavenging period to shorter than the default 7 days if we
> were to enable scavenging?
>
> There is a single DHCP server, but 2 DNS servers.
> Would it be a good idea to turn off the option of DHCP clients
> registering themselves into DNS and letting the DHCP server
> exclusively handle the DNS registrations? Wouldn't that eliminate the
> source of duplicate entries into DNS and thus eliminate the need of
> scavenging after the fact?
>
> I think duplicate entries are also occuring when laptops are carried
> to different floors and meeting rooms where they may be assigned new
> IP addresses in different subnets as it moves around the building even
> within the same day. Will scavenging do anything about these
> duplicate entries?

I am not that up on scavenging as I am learning it too.

I found that article about a day before I read your post and figured
I would pass it on.

What is your lease time on the DHCP assigned IP addresses?

I believe you could shorten the lease time so they can be
added back to the pool sooner.

As for the scavenging, I would want the DNS record removed when
the lease expires, so you may want to correpsond the times in
according to the DHCP lease time.

Take this information lightly as I am working on this same issue
too except that most of IP addresses are static and on one subnet.

Hopefully others here can correct me if I am mistaken.

moncho