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DHCP/DNS Duplicate entries

 
 
Greg Haslett
Guest
Posts: n/a
 
      29th Jan 2004
Hi
I am new to microsoft DNS/DHCP implimentations.
We have win2k servers for DNS DHCP.
What is happening is duplicate entries in the DNS database. (two different A
records for the same IP address) The scavenge time is set to 7 days and the
DHCP lease time is set to 2 days.
I have tried to perform a scavange stale resoure records but it did not
remove the duplicate entries.
any ideas ???


 
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Herb Martin
Guest
Posts: n/a
 
      30th Jan 2004
Are these dynamically registered? (Or manual?)

Same name, different IPs?

Consider using AD Integrated DNS but this shouldn't be happening
anyway.

--
Herb Martin
"Greg Haslett" <(E-Mail Removed)> wrote in message
news:uw6b$(E-Mail Removed)...
> Hi
> I am new to microsoft DNS/DHCP implimentations.
> We have win2k servers for DNS DHCP.
> What is happening is duplicate entries in the DNS database. (two different

A
> records for the same IP address) The scavenge time is set to 7 days and

the
> DHCP lease time is set to 2 days.
> I have tried to perform a scavange stale resoure records but it did not
> remove the duplicate entries.
> any ideas ???
>
>



 
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Greg Haslett
Guest
Posts: n/a
 
      30th Jan 2004
Hi
Thanks for your reply

Everything is dynamically registered.

I get Different names with the same Ip address in the DNS MMC.
I am Using the Win2000 AD DNS product.

Thanks


"Herb Martin" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Are these dynamically registered? (Or manual?)
>
> Same name, different IPs?
>
> Consider using AD Integrated DNS but this shouldn't be happening
> anyway.
>
> --
> Herb Martin
> "Greg Haslett" <(E-Mail Removed)> wrote in message
> news:uw6b$(E-Mail Removed)...
> > Hi
> > I am new to microsoft DNS/DHCP implimentations.
> > We have win2k servers for DNS DHCP.
> > What is happening is duplicate entries in the DNS database. (two

different
> A
> > records for the same IP address) The scavenge time is set to 7 days and

> the
> > DHCP lease time is set to 2 days.
> > I have tried to perform a scavange stale resoure records but it did not
> > remove the duplicate entries.
> > any ideas ???
> >
> >

>
>



 
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Deji Akomolafe
Guest
Posts: n/a
 
      30th Jan 2004
This is normal, but a bit cumbersome to explain. Let me try briefly. DHCP
lease duration: 2days. DNS Scavenging: 7days. ComputerA (say a Laptop) wakes
up on Monday and requestes an IP. DHCP gives it 1.1.1.1, and registers this
in DNS as an A record( ComputerA 1.1.1.1). ComputerA's user goes on a 3-day
vacation and takes his laptop with him. ComputerB user comes in on Thursday
and requests an IP. DHCP server has now put 1.1.1.1 in its pool of available
IPs (because it's over 2 days and ComputerA has not requested a renewal). So
ComputerB now gets 1.1.1.1 and this gets registered in DNS (ComputerB
1.1.1.1). This is NOT a duplicate. It's a different record altogether. And
remember, DNS has NOT cleaned up the old record (ComputerA 1.1.1.1) YET
because it's NOT more than 7 days old (scavenging length).

I hope that does not confuse you too terrinly. Now, what do we do with the
info? Follow this thread here:
http://www.mail-archive.com/activedi.../msg11017.html

and read more about Scavenging here:
http://www.microsoft.com/technet/pro...Scavenging.asp

--
Sincerely,

Dèjì Akómöláfé, MCSE MCSA MCP+I
www.akomolafe.com
www.iyaburo.com
Do you now realize that Today is the Tomorrow you were worried about
Yesterday? -anon
"Herb Martin" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Are these dynamically registered? (Or manual?)
>
> Same name, different IPs?
>
> Consider using AD Integrated DNS but this shouldn't be happening
> anyway.
>
> --
> Herb Martin
> "Greg Haslett" <(E-Mail Removed)> wrote in message
> news:uw6b$(E-Mail Removed)...
> > Hi
> > I am new to microsoft DNS/DHCP implimentations.
> > We have win2k servers for DNS DHCP.
> > What is happening is duplicate entries in the DNS database. (two

different
> A
> > records for the same IP address) The scavenge time is set to 7 days and

> the
> > DHCP lease time is set to 2 days.
> > I have tried to perform a scavange stale resoure records but it did not
> > remove the duplicate entries.
> > any ideas ???
> >
> >

>
>



 
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Greg Haslett
Guest
Posts: n/a
 
      30th Jan 2004
Thank you very much for the info I will try the suggestions

"Deji Akomolafe" <(E-Mail Removed)> wrote in message
news:Ov$(E-Mail Removed)...
> This is normal, but a bit cumbersome to explain. Let me try briefly. DHCP
> lease duration: 2days. DNS Scavenging: 7days. ComputerA (say a Laptop)

wakes
> up on Monday and requestes an IP. DHCP gives it 1.1.1.1, and registers

this
> in DNS as an A record( ComputerA 1.1.1.1). ComputerA's user goes on a

3-day
> vacation and takes his laptop with him. ComputerB user comes in on

Thursday
> and requests an IP. DHCP server has now put 1.1.1.1 in its pool of

available
> IPs (because it's over 2 days and ComputerA has not requested a renewal).

So
> ComputerB now gets 1.1.1.1 and this gets registered in DNS (ComputerB
> 1.1.1.1). This is NOT a duplicate. It's a different record altogether. And
> remember, DNS has NOT cleaned up the old record (ComputerA 1.1.1.1) YET
> because it's NOT more than 7 days old (scavenging length).
>
> I hope that does not confuse you too terrinly. Now, what do we do with the
> info? Follow this thread here:
> http://www.mail-archive.com/activedi.../msg11017.html
>
> and read more about Scavenging here:
>

http://www.microsoft.com/technet/pro...Scavenging.asp
>
> --
> Sincerely,
>
> Dèjì Akómöláfé, MCSE MCSA MCP+I
> www.akomolafe.com
> www.iyaburo.com
> Do you now realize that Today is the Tomorrow you were worried about
> Yesterday? -anon
> "Herb Martin" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Are these dynamically registered? (Or manual?)
> >
> > Same name, different IPs?
> >
> > Consider using AD Integrated DNS but this shouldn't be happening
> > anyway.
> >
> > --
> > Herb Martin
> > "Greg Haslett" <(E-Mail Removed)> wrote in message
> > news:uw6b$(E-Mail Removed)...
> > > Hi
> > > I am new to microsoft DNS/DHCP implimentations.
> > > We have win2k servers for DNS DHCP.
> > > What is happening is duplicate entries in the DNS database. (two

> different
> > A
> > > records for the same IP address) The scavenge time is set to 7 days

and
> > the
> > > DHCP lease time is set to 2 days.
> > > I have tried to perform a scavange stale resoure records but it did

not
> > > remove the duplicate entries.
> > > any ideas ???
> > >
> > >

> >
> >

>
>



 
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Herb Martin
Guest
Posts: n/a
 
      30th Jan 2004
You know that isn't much of a problem really.

Consider having the DHCP server do all the registration and to remove
entries
when a lease expires.

The only issue is that if I try to contact machine "ONE" I might get the IP
currently
being used by "THREE", or "NINE".

If you have plenty of IPs....
Try making your leases LONGER rather than shorter, so that the DHCP server
will not give out the address of one machine to another so quickly.

--
Herb Martin
"Greg Haslett" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi
> Thanks for your reply
>
> Everything is dynamically registered.
>
> I get Different names with the same Ip address in the DNS MMC.
> I am Using the Win2000 AD DNS product.
>
> Thanks
>
>
> "Herb Martin" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Are these dynamically registered? (Or manual?)
> >
> > Same name, different IPs?
> >
> > Consider using AD Integrated DNS but this shouldn't be happening
> > anyway.
> >
> > --
> > Herb Martin
> > "Greg Haslett" <(E-Mail Removed)> wrote in message
> > news:uw6b$(E-Mail Removed)...
> > > Hi
> > > I am new to microsoft DNS/DHCP implimentations.
> > > We have win2k servers for DNS DHCP.
> > > What is happening is duplicate entries in the DNS database. (two

> different
> > A
> > > records for the same IP address) The scavenge time is set to 7 days

and
> > the
> > > DHCP lease time is set to 2 days.
> > > I have tried to perform a scavange stale resoure records but it did

not
> > > remove the duplicate entries.
> > > any ideas ???
> > >
> > >

> >
> >

>
>



 
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Jonathan de Boyne Pollard
Guest
Posts: n/a
 
      30th Jan 2004
GH> any ideas ???

Have people release their DHCP leases before they remove their machines. (-:
 
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sharad
Guest
Posts: n/a
 
      1st Feb 2004
To delete the old dynamically updated records, thorugh
scavenging they must be older than No.of days set in
"No refresh Interval" + No. of days set in "Refresh Inverval" (So if both
are set to 7 days, a record has to
be older than 14 days, to get remove.)

Further as explained by Deji and Herb, thse are not "DUPLICATE Recrods"
and will not harm, UNLESS , for some reason, reverse lookup has to be
performed, (e.g. a software requires to perform revrse lookp, for those
dynamically updated record.) So if you are not using any such a software,
it's no harm.

If you still do not want those many unnecessary records there, then enable
scavening, and set "No refresh Interval" and "Refresh Interval" to lower
values e.g. 2 days each.

Sharad

"Greg Haslett" <(E-Mail Removed)> wrote in message
news:O$(E-Mail Removed)...
> Thank you very much for the info I will try the suggestions
>
> "Deji Akomolafe" <(E-Mail Removed)> wrote in message
> news:Ov$(E-Mail Removed)...
> > This is normal, but a bit cumbersome to explain. Let me try briefly.

DHCP
> > lease duration: 2days. DNS Scavenging: 7days. ComputerA (say a Laptop)

> wakes
> > up on Monday and requestes an IP. DHCP gives it 1.1.1.1, and registers

> this
> > in DNS as an A record( ComputerA 1.1.1.1). ComputerA's user goes on a

> 3-day
> > vacation and takes his laptop with him. ComputerB user comes in on

> Thursday
> > and requests an IP. DHCP server has now put 1.1.1.1 in its pool of

> available
> > IPs (because it's over 2 days and ComputerA has not requested a

renewal).
> So
> > ComputerB now gets 1.1.1.1 and this gets registered in DNS (ComputerB
> > 1.1.1.1). This is NOT a duplicate. It's a different record altogether.

And
> > remember, DNS has NOT cleaned up the old record (ComputerA 1.1.1.1) YET
> > because it's NOT more than 7 days old (scavenging length).
> >
> > I hope that does not confuse you too terrinly. Now, what do we do with

the
> > info? Follow this thread here:
> > http://www.mail-archive.com/activedi.../msg11017.html
> >
> > and read more about Scavenging here:
> >

>

http://www.microsoft.com/technet/pro...Scavenging.asp
> >
> > --
> > Sincerely,
> >
> > Dèjì Akómöláfé, MCSE MCSA MCP+I
> > www.akomolafe.com
> > www.iyaburo.com
> > Do you now realize that Today is the Tomorrow you were worried about
> > Yesterday? -anon
> > "Herb Martin" <(E-Mail Removed)> wrote in message
> > news:(E-Mail Removed)...
> > > Are these dynamically registered? (Or manual?)
> > >
> > > Same name, different IPs?
> > >
> > > Consider using AD Integrated DNS but this shouldn't be happening
> > > anyway.
> > >
> > > --
> > > Herb Martin
> > > "Greg Haslett" <(E-Mail Removed)> wrote in message
> > > news:uw6b$(E-Mail Removed)...
> > > > Hi
> > > > I am new to microsoft DNS/DHCP implimentations.
> > > > We have win2k servers for DNS DHCP.
> > > > What is happening is duplicate entries in the DNS database. (two

> > different
> > > A
> > > > records for the same IP address) The scavenge time is set to 7 days

> and
> > > the
> > > > DHCP lease time is set to 2 days.
> > > > I have tried to perform a scavange stale resoure records but it did

> not
> > > > remove the duplicate entries.
> > > > any ideas ???
> > > >
> > > >
> > >
> > >

> >
> >

>
>



 
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