NIC DNS Registration and Exchange Servers

Symptom

I recently worked with a customer who had introduced an Exchange 2013 Server into an existing Exchange 2007 environment. The issue was the 2013 Server was unable to send email anywhere; neither externally or to other Exchange Servers. If you executed the below command to view the status of the transport queues you received the below output:

Get-Queue <Queue Identity> | FL

Specifically, the error message you would receive is “4.4.0 DNS query failed. The error was: DNS query failed with error ErrorRetry”

This is a fairly common error indicating there is an issue contacting the DNS Server or Servers that Exchange is configured to use. ReferenceA ReferenceB

Resolution

However, in this case the issue was not obvious, unless you had already seen this issue before or knew a little bit about the health checks Exchange uses to ensure it’s healthy.

I remembered seeing a similar issue on a Reddit thread awhile back, which caused me to search and find this Microsoft KB article titled “DNS query failed” error when an email message is stuck in the Draft folder in an Exchange Server 2013 environment”.

This was the resolution in my scenario as well. To resolve the issue, I simply had to re-check the “Register this connection’s addresses in DNS” option on the IPv4> Properties>Advanced>DNS tab on the primary NIC used for Active Directory communications. While you can uncheck this box on secondary NICs (such as for iSCSI, Replication, Backup, etc.), it should always remain checked on the MAPI/Primary NIC. I’ve also seen issues where having this unchecked on a 2013/2016 DAG node will result in Managed Availability-triggered database failovers.

Bad NIC Settings Cause Internal Messages to Queue with 451 4.4.0 DNS query failed (nonexistent domain)

Overview:

I’ve come across this with customers a few times now & it can be a real head scratcher. However, the resolution is actually pretty simple.

 

Scenario:

Customer has multiple Exchange servers in the environment, or has just installed a 2^nd Exchange server into the environment. Customer is able to send directly out & receive in from the internet just fine but is unable to send email to/through another internal Exchange server.

This issue may also manifest itself as intermittent delays in sending between internal Exchange servers.

In either scenario, messages will be seen queuing & if you run a “Get-Queue –Identity QueueID | Formal-List” you will see a “LastError” of “451 4.4.0 DNS query failed. The error was: SMTPSEND.DNS.NonExistentDomain; nonexistent domain”.

 

Resolution:

This issue can occur because the Properties of the Exchange Server’s NIC have an external DNS server listed in them. Removing the external DNS server/servers & leaving only internal (Microsoft DNS/Active Directory Domain Controllers in most customer environments) DNS Servers; followed by restarting the Microsoft Exchange Transport Service should resolve the issue.

 

Summary:

The Default Configuration of an Exchange Server is to use the local Network Adapter’s DNS settings for Transport Service lookups.

(FYI: You can alter this in Exchange 07/10 via EMS using the Set-TransportServer command or in EMC>Server Configuration>Hub Transport>Properties of Server. Or in Exchange 2013 via EMS using the Set-TransportService command or via EAC>Servers>Edit Server>DNS Lookups. Using any of these methods, you can have Exchange use a specific DNS Server.)

Because the default behavior is to use the local network adapter’s DNS settings, Exchange was finding itself using external DNS servers for name resolution. Now this seemed to work fine when it had to resolve external domains/recipients but a public DNS server would likely have no idea what your internal Exchange servers (i.e. Ex10.contoso.local) resolve to.The error we see is due to the DNS server responding, but it just not having the A record for the internal host that we require. If the DNS server you had configured didn’t exist or wasn’t reachable you would actually see slightly different behavior (like messages sitting in “Ready” status in their respective queues).

 

An Exchange server, or any Domain-joined server for that matter, should not have its NICs DNS settings set to an external/ISPs DNS server (even as secondary). Instead, they should be set to internal DNS servers which have all the necessary records to discover internal Exchange servers.

 

References

http://support.microsoft.com/kb/825036

http://technet.microsoft.com/en-us/library/bb124896(v=EXCHG.80).aspx

“The DNS server address that is configured on the IP properties should be the DNS server that is used to register Active Directory records.”

http://technet.microsoft.com/en-us/library/aa997166(v=exchg.80).aspx

http://exchangeserverpro.com/exchange-2013-manually-configure-dns-lookups/

http://thoughtsofanidlemind.com/2013/03/25/exchange-2013-dns-stuck-messages/

 

How to reinstall a dynamic DNS Active Directory-integrated zone

Info based on KB294328 and revamped for 2003 and 2008

The following steps can remove the defective information in Active Directory-integrated DNS:

1. Go to the properties of the DNS zone files and change them to be a “Standard Primary”. (on 2008 un check the Box “Store the Zone in active directory”)
2. In the %Systemroot%\windows\System32\DNS folder, delete the text DNS Zones files.
3. Delete the object in Active Directory Users and Computers.
4. On the View menu, click Advanced Features, expand the System folder, click MicrosoftDNS, and then delete the zone file objects. (they may not exist here and that is OK)
5. For each Active Directory-integrated DNS server, repeat steps 1-3.
6. In the Transmission Control Protocol/Internet Protocol (TCP/IP) properties of the first Active Directory-integrated DNS server, point it to itself. For any other DNS servers, point all of them to the first DNS server that you bring up.
   NOTE: Do not change the properties of any additional Active Directory-integrated DNS servers to point to themselves until you have confirmed that a full and complete zone transfer has occurred from the first Active Directory-integrated DNS server after the rebuild process.
7. To obtain proper resolution, you must clear the Caching Resolver, which is the DNS client on the DNS server. At the command prompt, type: ipconfig /flushdns.
8. 8.Remove and re-add the DNS service (add remove/programs Windows Components->Networking services ),
9. In the DNS Server under the forward lookup Zones right click the domain (i.e. my domain.com) and the _msdcs Zones and select delete. (this will remove all static and stale data and allow DNS to re-generate Dynamic Data)
10. Now Re-create the zone you deleted (ie mydomain.local)
11. Stop and restart DNS and the NetLogon service..
    NOTE: You can use the net stop netlogon command and the net start netlogon command for the NetLogon service that registers information in DNS. Also, you can use the net stop dns and net start dns commands (to stop and start the DNS service) if DNS has not been totally removed. Or, you can stop and start the NetLogon service and the DNS service in Control Panel, in Services, or you can restart the computer.

You have completed the process to clear out a DNS server.

You must complete the process for any additional DNS servers that you plan to integrate with Active Directory.

The following steps can assist you to build a strong foundation for DNS, Active Directory, and FRS:

1. Configure all DNS servers to point to the same DNS server in the domain or forest under TCP/IP properties in DNS: Right-click My Network Places, click Local Area Connection, right-click Local Area Connection, click Properties, select the properties of TCP/IP, and then point all DNS servers to the same DNS server. Also, click the Advanced DNS tab, and then confirm that secondary DNS servers are not configured.
2. Re-add the DNS service, or re-add the zones and configure them to be Active Directory integrated. For troubleshooting purposes, you may want to set “Allow Dynamic Updates?” to Yes. Later, you can change this setting to “Allow Only Secure Updates”.
3. Stop the DNS service and the NetLogon service by using either a command or the Computer Management snap-in.
4. Run the ipconfig /flushdns command, and then run the ipconfig /registerdns comand. This command can help you to register your A resource record for DNS as well as your start of authority (SOA). You may want to run this command on any other servers that are critical to you.
   NOTE: The Dynamic Host Configuration Protocol (DHCP) client service needs to be running on each of these computers to register the records in Dynamic DNS. It is not relevant if the computer is a DHCP client or not. You must have this service set to “start” and the “Start up” type set to “automatic.” The DHCP client service is what registers records in Dynamic DNS. (Refer to the description in the Computer Management snap-in.)
5. Active Directory-integrated DNS is now working on your first Dynamic DNS server. You must point additional Dynamic DNS servers to the first DNS server under TCP/IP properties. You must confirm that a full and complete replication process has occurred before you change the TCP/IP properties to point to itself for any additional DNS servers.