A Records disappearing

  • Thread starter Thread starter Halo5011
  • Start date Start date
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Halo5011

Hi All,

we have had the strangest occurrence for the past two weeks on our dns
server. users called and reported issues w/ receiving emails , accessing
calendars and upon investigating the matter further, we found out that A
record does not exist for that particular exchange server on our DNS server.
this happened on two of our exchange server , once two weeks ago and once
this morning. six months ago, this happened to our domain controller in our
branch office. recreating the A record fixes the issue, but why would this
happen on it's own?
has anyone seen this issue? any help would be appreciated.

Regards,

halo5011.
 
There are only 2 ways the record could have been removed, IMO:
1. Manually removed by an admin
2. Scavenged by DNS itself

1. If using ADI zones, use auditing to ascertain who removed the object.
2. Check scavenging config(as well as TTL settings)

What zone types do you have?
Do you have DDNS enabled?
Are servers perfoming DDNS updates for their records?

neil
 
Neil,

we are using ADI zones. i've checked the scavenging config , it's enabled
and no-refresh and refresh are set to 7 days. we do have ddns enabled but
i'm not sure how to check whether servers are performing ddns updates for
their records.

halo5011.
 
Exch server
========
Goto TCPIP properties and then select the DNS tab.
Is "Register this connections' ..." enabled? It should be if you wish the
server to perform DDNS of its DNS records.

DNS Server
========
In the DNS snap-in, select View/Advanced
Select a record and view its properties
You'll see when the record was last updated (using DDNS) and if the record
will be removed if allowed to go stale (via scavenging),

hth,
neil
 
Neil,

register this connections is not enabled on the tcp properties for both of
our exchange servers and these are the two exchange servers that lost the A
records in DNS. you think that's why it decided to remove the A records for
these servers as it thought that they were not active?

halo5011.
 
This means that the exch servers are not performing DDNS updates. As a
result, their DNS records are becoming stale after the TTL expires.
Scavenging will eventually remove the records.

Enable the setting on the servers.

neil
 
Neil,

once again, i appreciate your help on this matter. something very strange
happened today. the A record for one of our exchange servers got replaced
w/ another IP address and strangely enough, it got replaced
w/ an IP address from our DHCP scope which happens to be hosted on our
exchange server. (thsi exchange server acts as a dhcp server for our
workstations). any ideas Neil? i'm now more confused than ever.

Regards,

Elman.
 
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