I'm having a problem with a new Exchange 2013 CU7 server on Windows Server 2012 R2.  Having intermittent 451 4.7.1 Temporary server error. Please try again later PRX2 on receiving mail on connectors configured with port 25.  I keep thinking I have solved the issue.  If I think I fix it in the morning, it works all afternoon.  The next day I'm getting the error again.  It is driving me and my client nuts!

The Exchange server has the DNS servers for the internal DC's set in EAC for both internal and external lookups.

The DC's have DNS set to forward to external DNS servers.  I 'm having no issues with DNS resolution anywhere in the environment.

The Exchange server is able to resolve internal and external DNS.

One thing of note and I'm not sure if this is normal, if I ping the DC's i get back IPv6 address, never an IP4.  I have even set the servers in a host file.

Thankfully I have a filtered mail service that will spool mail if it cannot connect to the mail server and retires at set intervals.  So I have not lost any emails.

There is no filtering or AV scanning happening on the server or Exchange level.

Nothing in the event logs of note related to this issue.

At the moment it is working, but I'm sure it's going to stop again soon.

Hi

At the time you lose connection to the DC are you able to ping it? Do you have any AV on the DC's that could be stopping connections?

adding to the hosts file shouldnt be done on your internal network if DNS is working properly as your machine will query the host file first.

Is the windows firewall enabled at all on the Exchange servers? Can you disable it and see?

IPv6 response is fine. you shouldnt disable it.

Yes, I'm able to ping it.  The error is happening again.  There is no rhyme or reason to this.

Turned off the firewall, still happening.

And now it's working again.  I'm looking for a pattern but can't find one.

• Edited by Dynamic Computer Thursday, January 22, 2015 6:28 PM

Happening again.  Perhaps it's a 20 minute cycle?

Hi ,

1.On the default front end receive connectors just go to the network adapter settings and bound it to a ip address of the cas server and check the results.By default it will be set to all the available ipv4 address.

2.If you have multiple network cards on the cas servers then you need to set the binding of the network adapter in the first order that should have the Ip address of the cas server.

If your hosted MTA is receiving a 451 4.7.1 then your Exchange server is actually issuing that and is listening so I doubt it's a DNS resolution issue. You can confirm if you can pull the SMTP logs of your MTA and check the SMTP session to confirm if your Exchange server is issuing 451 4.7.1.

Since this is a receiving problem and you're getting the 451 4.7.1 are you sure it's not your hosted MTA that is actually issuing this to the sender and not your Exchange server? Log into your hosted provider and disable any greylisting temporarily to eliminate.

I set the IP address of the CAS server for the default front end receiver.

Still happening.

Don't know if this will help.

Error in processing. The server response was: 4.7.0 Temporary server error. Please try again later. PRX2  || Erro Stack Trace:    at System.Net.Mail.DataStopCommand.CheckResponse(SmtpStatusCode statusCode, String serverResponse)
   at System.Net.Mail.DataStopCommand.Send(SmtpConnection conn)
   at System.Net.Mail.SmtpConnection.OnClose(Object sender, EventArgs args)
   at System.Net.ClosableStream.Close()
   at System.Net.Mail.MailWriter.Close()
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at TestaSmtp.Form1.btnTestar_Click(Object sender, EventArgs e)

are you sure it's not your hosted MTA that is actually issuing this to the sender and not your Exchange server? 

Yes.  It happens when I send mail to the connector from within the network as well.

You're sure you're not running any other AV\SPAM on the Exchange server? Any transport events in eventvwr?

Internal users are also complaining that they are sending emails do not show up in the sent items.

Don't know if this is related.

Hmm doesn't show up even in OWA sent items? Any transport events in eventvwr?

No not anything third party.  What's turned on by default on Exchange server?

No Transport errors.  

I get this in the log, but since I'm not doing TLS, I didn't think it mattered, but maybe it's of note.

Microsoft Exchange could not find a certificate that contains the domain name server.domain.local in the personal store on the local computer. Therefore, it is unable to support the STARTTLS SMTP verb for the connector External Send to GFI with a FQDN parameter of server.domain.local. If the connector's FQDN is not specified, the computer's FQDN is used. Verify the connector configuration and the installed certificates to make sure that there is a certificate with a domain name for that FQDN. If this certificate exists, run Enable-ExchangeCertificate -Services SMTP to make sure that the Microsoft Exchange Transport service has access to the certificate key.

Hmmmmm I am seeing a bunch of these, they may correspond to when I have the issues:

Inbound authentication failed with error LogonDenied for Receive connector Default server.domain.local. The authentication mechanism is Ntlm. The source IP address of the client who tried to authenticate to Microsoft Exchange is [X.X.X.X].

The IP address listed above is coming from the test external network I'm using to test the receive connector.  As far as I know I'm not trying to login with NTLM.

• Edited by Dynamic Computer Thursday, January 22, 2015 9:41 PM

I wouldn't worry about the cert for now Exchange will use opportunistic TLS when it can if it can't it just falls back to the default plain text. 

the inbound auth failure may be of concern, your test client appears to be connecting to a receive connector that is requiring authentication. Your relay receive connector should have the following permissions below. 

Transport layer security
Externally Secured
Exchange Servers
Anonymous users

If you didn't create a dedicated receive connector, try creating a new relay connector with those permissions and test again.

http://www.petenetlive.com/KB/Article/0000891.htm

No, she did tell me that Outlook  2013 crashed when it happened.  That's another thing that has been happening.  No transport events.

It was really bothering me so I fixed the cert problem.

I also created a new receive connector running on a different IP address.

I thought it was working, until it stopped working again.

I'm really starting to not like Exchange 2013.  Exchange 2003 practically ran itself. :(

I'm now getting these since fixing the cert, don't know if it helps figure out what's going on:

Inbound authentication failed with error LogonDenied for Receive connector Client Frontend EXCH1. The authentication mechanism is Login. The source IP address of the client who tried to authenticate to Microsoft Exchange is [127.0.0.1].

This is making me nuts.  Working, not working, working, not working....

• Edited by Dynamic Computer Friday, January 23, 2015 7:02 AM

Does this info help?

FrontEndTransport...                      FrontendTran... Healthy
FrontendTransport...                      FrontendTran... Healthy
OnPremisesInbound...                      FrontendTran... Unhealthy
OnPremisesSmtpCli...                      FrontendTran... Unhealthy
PrivateWorkingSet... msexchangefronten... FrontendTran... Healthy
PrivateWorkingSet... msexchangefronten... FrontendTran... Healthy
ProcessProcessorT... msexchangefronten... FrontendTran... Healthy
ProcessProcessorT... msexchangefronten... FrontendTran... Healthy
FrontendTransport... FrontendTransport    FrontendTran... Healthy
InboundProxyDesti... FrontendTransport    FrontendTran... Healthy
InboundProxyDesti... FrontendTransport    FrontendTran... Healthy
InboundProxyAccou... FrontendTransport    FrontendTran... Healthy
InboundProxyAccou... FrontendTransport    FrontendTran... Healthy
ResourceForestMis... FrontendTransport    FrontendTran... Healthy
FETBackpressureSu...                      FrontendTran... Healthy
CrashEvent.msexch... msexchangefronten... FrontendTran... Healthy

Get-ServerHealth -Identity EXCH1 -HealthSet Network

DnsHostRecordMonitor Network              Network         Unhealthy
NetworkAdapterMon...                      Network         Healthy
NetworkAdapterRss...                      Network         Healthy

 HealthSet           AlertValue          LastTransitionTime  Monito
 ---------           ----------          ------------------  ------
 ActiveSync          Unhealthy           1/20/2015 12:31:... 2
 Autodiscover        Unhealthy           1/20/2015 12:15:... 3
 AMScanTimeout       Healthy             12/24/2014 9:56:... 6
 AMScanError         Healthy             12/24/2014 10:04... 12
 AMMessagesDeferred  Healthy             12/24/2014 9:56:... 1
 ActiveSync.Protocol Unhealthy           1/22/2015 3:00:2... 7
 Autodiscover.Pro... Unhealthy           1/19/2015 11:43:... 8
 AMADError           Healthy             12/24/2014 9:58:... 2
 AMTenantConfigError Healthy             12/24/2014 9:58:... 1
 DLExpansion         Healthy             12/24/2014 9:59:... 3
 ECP                 Unhealthy           1/20/2015 9:23:3... 10
 Compliance          Healthy             1/20/2015 9:32:1... 29
 AD                  Healthy             12/24/2014 10:05... 24
 Autodiscover.Proxy  Unhealthy           1/20/2015 12:16:... 1
 ActiveSync.Proxy    Unhealthy           1/20/2015 12:17:... 1
 ECP.Proxy           Healthy             12/24/2014 9:56:... 1
 EWS.Proxy           Unhealthy           1/20/2015 12:17:... 1
 OutlookMapiHttp.... Unhealthy           1/20/2015 12:17:... 6
 OAB.Proxy           Unhealthy           1/20/2015 12:17:... 1
 OWA.Proxy           Healthy             12/24/2014 9:56:... 2
 RPS.Proxy           Healthy             12/24/2014 10:01... 6
 RWS.Proxy           Healthy             12/24/2014 10:01... 11
 EventAssistants     Healthy             12/24/2014 10:22... 6
 EWS.Protocol        Unhealthy           12/30/2014 12:59... 8
 AMScanners          Healthy             12/24/2014 9:56:... 2
 EWS                 Unhealthy           12/30/2014 1:20:... 3
 AMEUS               Healthy             12/24/2014 9:56:... 4
 DataProtection      Healthy             12/24/2014 2:55:... 36
 Monitoring          Healthy             12/24/2014 10:01... 20
 Clustering          Healthy             12/24/2014 12:49... 5
 UM.CallRouter       Healthy             12/24/2014 10:00... 10
 UM.Protocol         Healthy             12/25/2014 5:17:... 23
 OAB                 Healthy             12/24/2014 10:01... 10
 EAS                 Healthy             12/24/2014 9:59:... 2
 Search              Healthy             1/5/2015 11:22:5... 48
 AMScannerCrash      Healthy             12/24/2014 9:56:... 1
 FreeBusy            Healthy             12/24/2014 9:59:... 2
 BitlockerDeployment Healthy             12/24/2014 9:57:... 2
 ClientAccess.Proxy  Healthy             12/24/2014 10:01... 2
 Transport           Healthy             12/24/2014 10:01... 2
 EDS                 Healthy             12/24/2014 10:52... 44
 AMFMSService        Healthy             12/24/2014 10:01... 6
 ExtendedReportWeb   Healthy             12/24/2014 10:01... 7
 FrontendTransport   Unhealthy           1/22/2015 2:46:5... 16
 FEP                 Healthy             12/24/2014 9:59:... 2
 FfoRws              Healthy             12/24/2014 9:57:... 2
 Places              Healthy             12/24/2014 9:59:... 2
 RemoteMonitoring    Healthy             12/24/2014 10:01... 3
 Inference           Healthy             12/24/2014 10:01... 2
 OWA                 Unhealthy           1/19/2015 11:32:... 18
 HubTransport        Unhealthy           1/22/2015 3:14:3... 97
 OWA.Protocol.Dep    Healthy             12/24/2014 10:38... 2
 Network             Unhealthy           1/23/2015 12:52:... 3
 MailboxSpace        Healthy             12/24/2014 10:09... 3
 MailboxTransport    Healthy             12/24/2014 10:06... 25
 MailboxMigration    Healthy             12/24/2014 10:08... 25
 OWA.Protocol        Healthy             1/20/2015 9:24:5... 6
 PublicFolders       Healthy             12/24/2014 10:10... 6
 ProcessIsolation    Healthy             12/24/2014 10:01... 25
 SiteMailbox         Healthy             12/24/2014 10:05... 3
 RPS                 Unhealthy           1/19/2015 11:52:... 12
 Outlook.Protocol    Healthy             1/20/2015 9:35:4... 17
 OutlookMapiHttp.... Healthy             1/20/2015 9:31:5... 2
 OutlookMapiHttp     Healthy             1/20/2015 9:31:2... 1
 Outlook             Healthy             1/20/2015 9:29:1... 1
 UserThrottling      Healthy             12/24/2014 10:22... 7
 Store               Healthy             1/5/2015 11:09:0... 32
 DAL                 Healthy             12/24/2014 9:57:... 21
 AntiSpam            Healthy             12/24/2014 10:00... 5
 Security            Healthy             12/24/2014 10:00... 11
 IMAP.Protocol       Healthy             12/24/2014 10:01... 10
 CentralAdmin        Healthy             12/24/2014 10:01... 5
 Datamining          Healthy             12/24/2014 10:01... 10
 Provisioning        Healthy             12/24/2014 10:00... 5
 POP.Protocol        Healthy             12/24/2014 10:00... 10
 Calendaring         Healthy             12/24/2014 10:01... 5
 Psws                Healthy             12/24/2014 10:01... 10
 PushNotification... Healthy             12/24/2014 10:00... 5
 MessageTracing      Healthy             12/24/2014 10:01... 5
 Outlook.Proxy       Unhealthy           1/20/2015 12:16:... 6
 Antimalware         Healthy             12/24/2014 10:00... 2
 JournalArchive      Healthy             12/24/2014 10:01... 1
 EmailManagement     Healthy             12/24/2014 9:59:... 2
 AMService           Healthy             12/24/2014 10:01... 6
 FIPS                Healthy             12/24/2014 10:01... 7
 FfoCentralAdmin     Healthy             12/24/2014 9:58:... 2
 UnifiedMailbox      Healthy             12/24/2014 9:56:... 4
 UnifiedGroups       Healthy             12/24/2014 9:56:... 21
 OWA.Attachments     Healthy             12/24/2014 9:56:... 26
 PeopleConnect       Healthy             12/24/2014 9:56:... 8
 RemoteStore         Healthy             12/24/2014 9:58:... 1
 OWA.WebServices     Healthy             12/24/2014 9:56:... 1
 HDPhoto             Healthy             12/24/2014 9:56:... 10
 HxService.Calendar  Healthy             12/24/2014 9:56:... 7
 HxService.Mail      Healthy             12/24/2014 9:59:... 15
 OWA.SuiteServices   Healthy             12/24/2014 9:56:... 2
 SharedCache         Healthy             12/24/2014 10:01... 5
 FfoUcc              Healthy             12/24/2014 10:01... 5
 E4E                 Healthy             12/24/2014 10:01... 5
 FfoMonitoring       Disabled            1/1/0001 12:00:0... 23



Hi ,

Have you checked my suggestions ?

Yes, I did this already.

Any other ideas?  This is a brand new server.  I don't understand why this is happening.  Is there a bug with CU7?

I really need some help with this.

If it's a bug then I need free support resources from Microsoft Product support.

Hi,

Per my experience, this issue should be caused by DNS issues, I suggest we check the following steps one by one:

1. Check the two boxes in the advance network configuration:

2. Check the alternative DNS and preferred DNS, please removed the secondary DNS which does not point to our internal DNS/Domain Controller (if there is).

Related 3^rd article:

Title: https://gerhardwessels.wordpress.com/2013/05/06/451-4-7-0-temporary-server-error-please-try-again-later-prx2/

Link: I simply removed the secondary DNS which does not point to my internal DNS/Domain Controller and now I am able to receive email.

3. Check the DNS lookups settings for the Exchange 2013 mailbox servers, make sure we used the NIC of both internal and external:

4. Also check the server components by running:

Get-ServerComponentState -Identity Server_Name

If there is any component state inactive, we should bring them to active:

Get-ServerComponentState -Identity Server_Name | Set-ServerComponentState -Requester Functional -State Active Component: ServerWideOffline

Thanks,

Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com

Those boxes are checked.

DNS is set only to internal DNS servers in both the NIC config and in EAC.

I am also running hyper-V on this server and the NIC is set as part of a virutal switch. Don't know if that bit of info helps.

As far as component state, the results are the same whether not the server is receiving mail or not, again in 15 minute increments.

ServerWideOffline                       Active HubTransport                            Active FrontendTransport                       Active Monitoring                              Active RecoveryActionsEnabled                  Active AutoDiscoverProxy                       Inactive ActiveSyncProxy                         Inactive EcpProxy                                Active EwsProxy                                Inactive ImapProxy                               Active OabProxy                                Inactive OwaProxy                                Active PopProxy                                Active PushNotificationsProxy                  Active RpsProxy                                Active RwsProxy                                Active RpcProxy                                Inactive UMCallRouter                            Active XropProxy                               Active HttpProxyAvailabilityGroup              Active ForwardSyncDaemon                       Inactive ProvisioningRps                         Inactive MapiProxy                               Inactive EdgeTransport                           Active HighAvailability                        Active SharedCache                             Active

Now I'm getting this when sending mail to the receive connector:

Insufficient system resources

I have not idea why.  I don't see any problems with hard disk or memory.

As far as the PRX2 problem, perhaps this is a clue.

I'm getting these every 15  minutes.  Please note, this is the same time interval for when I have the PRX2 problem.

Log Name:      Application
Source:        MSExchangeFrontEndTransport
Date:          1/24/2015 9:39:01 AM
Event ID:      1035
Task Category: SmtpReceive
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      server
Description:
Inbound authentication failed with error LogonDenied for Receive connector Client Frontend server. The authentication mechanism is Login. The source IP address of the client who tried to authenticate to Microsoft Exchange is [127.0.0.1].

I could send saved event logs that might help.  You can contact me at jazzmans2 at hotmail.com.

Hi ,

On the server which you are facing the issue please check did you have enough space on the disk where the queue database resides.

Yes, 47GB free.

I find that if I restart the front end transport while I'm having the problem, I'm able to receive mail again until the next time interval.

Also restarting the front end transport yields this in the logs

Anti-spam agents are enabled, but the list of internal SMTP servers is empty. If there are any MTAs between this server and the Internet, populate this list by using the Set-TransportConfig cmdlet in the Exchange Management Shell.

I also noticed that I was getting active directory lookup errors on the Exchange server yesterday when our primary DC was down for maintenance.  We have a backup DC running as a hyper-v on the server that has Exchange server.  The Exchange server does have the DNS address of the backup DC populated in both the NIC and Exchange server properties.

As an example I received these:

 Active Manager Client experienced an AD timeout trying to lookup object ExchangeServer1 in 00:01:00.

Hi ,

Please set the dns servers for the exchange servers through the below mentioned command and check the results .

Set-TransportService -InternalDNSServers "ip address of your domain controllers"

Great suggestion I did a:

get-transportservice |FL and did notice the internalDNSServers entry is empty.

What is the proper syntax for entering more than one dns server?

Also it's asking for an identity, and I'm not sure what to put.  I tried putting the server name and all I get is a blinking cursor.

Hi ,

Set-TransportService -InternalDNSServers "ip address of your domain controllers"

You can delimit the ip addresses by using the comma symbol.

for instance :

Set-TransportService -identity "mailbox server name" -InternalDNSServers "192.168.1.10,192.168.1.20"

On the above example i would assume the mentioned ip address as your domain controllers ip address.

No, it will not allow me to delimit with a comma.

[PS] C:\Windows\system32>Set-TransportService -InternalDNSServers "192.168.1.1,192.168.1.8"
Cannot process argument transformation on parameter 'InternalDNSServers'. Cannot convert value
"192.168.1.1,192.168.1.8" to type "Microsoft.Exchange.Data.MultiValuedProperty`1[System.Net.IPAddress]". Error:
"Failed to convert 192.168.1.1,192.168.1.8 from System.String to System.Net.IPAddress. Error: Error while convert
string '192.168.1.1,192.168.1.8' to result type System.Net.IPAddress: An invalid IP address was specified."
    + CategoryInfo          : InvalidData: (:) [Set-TransportService], ParameterBindin...mationException
    + FullyQualifiedErrorId : ParameterArgumentTransformationError,Set-TransportService
    + PSComputerName        : server1

Hi ,

Set-TransportService -identity "mailbox server name" -InternalDNSServers "ip address of your domain controllers"

You can delimit the ip addresses by using the comma symbol.

for instance :

Set-TransportService -identity "mailbox server name" -InternalDNSServers "192.168.1.10,192.168.1.20"

On the above example i would assume the mentioned ip address as your domain controllers ip address.

Here is the output of the get transportservice command if it is helpful

RunspaceId                                         : 928db722-79f4-4c74-b445-29910607b788
Name                                               : EXCH1
AntispamAgentsEnabled                              : False
ConnectivityLogEnabled                             : True
ConnectivityLogMaxAge                              : 30.00:00:00
ConnectivityLogMaxDirectorySize                    : 1000 MB (1,048,576,000 bytes)
ConnectivityLogMaxFileSize                         : 10 MB (10,485,760 bytes)
ConnectivityLogPath                                : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\Connectivity
DelayNotificationTimeout                           : 04:00:00
ExternalDNSAdapterEnabled                          : True
ExternalDNSAdapterGuid                             : 105cf317-1847-43d4-932e-186e1ff24c39
ExternalDNSProtocolOption                          : Any
ExternalDNSServers                                 : {}
ExternalIPAddress                                  :
InternalDNSAdapterEnabled                          : True
InternalDNSAdapterGuid                             : 105cf317-1847-43d4-932e-186e1ff24c39
InternalDNSProtocolOption                          : Any
InternalDNSServers                                 : {192.168.1.1}
MaxConcurrentMailboxDeliveries                     : 20
MaxConcurrentMailboxSubmissions                    : 20
MaxConnectionRatePerMinute                         : 1200
MaxOutboundConnections                             : 1000
MaxPerDomainOutboundConnections                    : 20
MessageExpirationTimeout                           : 2.00:00:00
MessageRetryInterval                               : 00:15:00
MessageTrackingLogEnabled                          : True
MessageTrackingLogMaxAge                           : 30.00:00:00
MessageTrackingLogMaxDirectorySize                 : 1000 MB (1,048,576,000 bytes)
MessageTrackingLogMaxFileSize                      : 10 MB (10,485,760 bytes)
MessageTrackingLogPath                             : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\MessageTracking
IrmLogEnabled                                      : True
IrmLogMaxAge                                       : 30.00:00:00
IrmLogMaxDirectorySize                             : 250 MB (262,144,000 bytes)
IrmLogMaxFileSize                                  : 10 MB (10,485,760 bytes)
IrmLogPath                                         : C:\Program Files\Microsoft\Exchange Server\V15\Logging\IRMLogs
ActiveUserStatisticsLogMaxAge                      : 30.00:00:00
ActiveUserStatisticsLogMaxDirectorySize            : 250 MB (262,144,000 bytes)
ActiveUserStatisticsLogMaxFileSize                 : 10 MB (10,485,760 bytes)
ActiveUserStatisticsLogPath                        : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\ActiveUsersStats
ServerStatisticsLogMaxAge                          : 30.00:00:00
ServerStatisticsLogMaxDirectorySize                : 250 MB (262,144,000 bytes)
ServerStatisticsLogMaxFileSize                     : 10 MB (10,485,760 bytes)
ServerStatisticsLogPath                            : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\ServerStats
MessageTrackingLogSubjectLoggingEnabled            : True
OutboundConnectionFailureRetryInterval             : 00:10:00
IntraOrgConnectorProtocolLoggingLevel              : None
PickupDirectoryMaxHeaderSize                       : 64 KB (65,536 bytes)
PickupDirectoryMaxMessagesPerMinute                : 100
PickupDirectoryMaxRecipientsPerMessage             : 100
PickupDirectoryPath                                : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Pickup
PipelineTracingEnabled                             : False
ContentConversionTracingEnabled                    : False
PipelineTracingPath                                : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\PipelineTracing
PipelineTracingSenderAddress                       :
PoisonMessageDetectionEnabled                      : True
PoisonThreshold                                    : 2
QueueMaxIdleTime                                   : 00:03:00
ReceiveProtocolLogMaxAge                           : 30.00:00:00
ReceiveProtocolLogMaxDirectorySize                 : 250 MB (262,144,000 bytes)
ReceiveProtocolLogMaxFileSize                      : 10 MB (10,485,760 bytes)
ReceiveProtocolLogPath                             : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\ProtocolLog\SmtpReceive
RecipientValidationCacheEnabled                    : False
ReplayDirectoryPath                                : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Replay
RootDropDirectoryPath                              :
RoutingTableLogMaxAge                              : 7.00:00:00
RoutingTableLogMaxDirectorySize                    : 50 MB (52,428,800 bytes)
RoutingTableLogPath                                : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\Routing
SendProtocolLogMaxAge                              : 30.00:00:00
SendProtocolLogMaxDirectorySize                    : 250 MB (262,144,000 bytes)
SendProtocolLogMaxFileSize                         : 10 MB (10,485,760 bytes)
SendProtocolLogPath                                : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\ProtocolLog\SmtpSend
TransientFailureRetryCount                         : 6
TransientFailureRetryInterval                      : 00:05:00
AntispamUpdatesEnabled                             : False
InternalTransportCertificateThumbprint             : B7A4E875601085D09D8656F9C5E7B2D83F376D22
TransportSyncEnabled                               : False
TransportSyncPopEnabled                            : False
WindowsLiveHotmailTransportSyncEnabled             : False
TransportSyncExchangeEnabled                       : False
TransportSyncImapEnabled                           : False
MaxNumberOfTransportSyncAttempts                   : 3
MaxActiveTransportSyncJobsPerProcessor             : 16
HttpTransportSyncProxyServer                       :
HttpProtocolLogEnabled                             : False
HttpProtocolLogFilePath                            :
HttpProtocolLogMaxAge                              : 7.00:00:00
HttpProtocolLogMaxDirectorySize                    : 250 MB (262,144,000 bytes)
HttpProtocolLogMaxFileSize                         : 10 MB (10,485,760 bytes)
HttpProtocolLogLoggingLevel                        : None
TransportSyncLogEnabled                            : False
TransportSyncLogFilePath                           :
TransportSyncLogLoggingLevel                       : None
TransportSyncLogMaxAge                             : 30.00:00:00
TransportSyncLogMaxDirectorySize                   : 10 GB (10,737,418,240 bytes)
TransportSyncLogMaxFileSize                        : 10 MB (10,485,760 bytes)
TransportSyncHubHealthLogEnabled                   : False
TransportSyncHubHealthLogFilePath                  :
TransportSyncHubHealthLogMaxAge                    : 30.00:00:00
TransportSyncHubHealthLogMaxDirectorySize          : 10 GB (10,737,418,240 bytes)
TransportSyncHubHealthLogMaxFileSize               : 10 MB (10,485,760 bytes)
TransportSyncAccountsPoisonDetectionEnabled        : False
TransportSyncAccountsPoisonAccountThreshold        : 2
TransportSyncAccountsPoisonItemThreshold           : 2
TransportSyncAccountsSuccessivePoisonItemThreshold : 3
TransportSyncRemoteConnectionTimeout               : 00:01:40
TransportSyncMaxDownloadSizePerItem                : 36 MB (37,748,736 bytes)
TransportSyncMaxDownloadSizePerConnection          : 50 MB (52,428,800 bytes)
TransportSyncMaxDownloadItemsPerConnection         : 1000
DeltaSyncClientCertificateThumbprint               :
UseDowngradedExchangeServerAuth                    : False
IntraOrgConnectorSmtpMaxMessagesPerConnection      : 20
TransportSyncLinkedInEnabled                       : False
TransportSyncFacebookEnabled                       : False
QueueLogMaxAge                                     : 7.00:00:00
QueueLogMaxDirectorySize                           : 200 MB (209,715,200 bytes)
QueueLogMaxFileSize                                : 10 MB (10,485,760 bytes)
QueueLogPath                                       : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\QueueViewer
WlmLogMaxAge                                       : 7.00:00:00
WlmLogMaxDirectorySize                             : 250 MB (262,144,000 bytes)
WlmLogMaxFileSize                                  : 10 MB (10,485,760 bytes)
WlmLogPath                                         : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\WLM
AgentLogMaxAge                                     : 7.00:00:00
AgentLogMaxDirectorySize                           : 250 MB (262,144,000 bytes)
AgentLogMaxFileSize                                : 10 MB (10,485,760 bytes)
AgentLogPath                                       : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\Hub\AgentLog
AgentLogEnabled                                    : True
FlowControlLogMaxAge                               : 7.00:00:00
FlowControlLogMaxDirectorySize                     : 200 MB (209,715,200 bytes)
FlowControlLogMaxFileSize                          : 10 MB (10,485,760 bytes)
FlowControlLogPath                                 :
FlowControlLogEnabled                              : True
ProcessingSchedulerLogMaxAge                       : 7.00:00:00
ProcessingSchedulerLogMaxDirectorySize             : 200 MB (209,715,200 bytes)
ProcessingSchedulerLogMaxFileSize                  : 10 MB (10,485,760 bytes)
ProcessingSchedulerLogPath                         :
ProcessingSchedulerLogEnabled                      : True
ResourceLogMaxAge                                  : 7.00:00:00
ResourceLogMaxDirectorySize                        : 200 MB (209,715,200 bytes)
ResourceLogMaxFileSize                             : 10 MB (10,485,760 bytes)
ResourceLogPath                                    :
ResourceLogEnabled                                 : True
DnsLogMaxAge                                       : 7.00:00:00
DnsLogMaxDirectorySize                             : 100 MB (104,857,600 bytes)
DnsLogMaxFileSize                                  : 10 MB (10,485,760 bytes)
DnsLogPath                                         :
DnsLogEnabled                                      : False
JournalLogMaxAge                                   : 7.00:00:00
JournalLogMaxDirectorySize                         : 200 MB (209,715,200 bytes)
JournalLogMaxFileSize                              : 10 MB (10,485,760 bytes)
JournalLogPath                                     : C:\Program Files\Microsoft\Exchange
                                                     Server\V15\TransportRoles\Logs\JournalLog
JournalLogEnabled                                  : False
TransportMaintenanceLogMaxAge                      : 7.00:00:00
TransportMaintenanceLogMaxDirectorySize            : 200 MB (209,715,200 bytes)
TransportMaintenanceLogMaxFileSize                 : 10 MB (10,485,760 bytes)
TransportMaintenanceLogPath                        :
TransportMaintenanceLogEnabled                     : True
SmtpEnableAllTlsVersions                           : False
Identity                                           : EXCH1
IsValid                                            : True
ExchangeVersion                                    : 0.1 (8.0.535.0)
DistinguishedName                                  : CN=EXCH1,CN=Servers,CN=Exchange Administrative Group
                                                     (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=KSD,CN=Microsoft
                                                     Exchange,CN=Services,CN=Configuration,DC=ksd,DC=local
Guid                                               : aebc9665-dfbb-4646-b5f0-565be6aa5f29
ObjectCategory                                     : ksd.local/Configuration/Schema/ms-Exch-Exchange-Server
ObjectClass                                        : {top, server, msExchExchangeServer}
WhenChanged                                        : 1/29/2015 11:47:38 AM
WhenCreated                                        : 12/24/2014 1:39:57 AM
WhenChangedUTC                                     : 1/29/2015 4:47:38 PM
WhenCreatedUTC                                     : 12/24/2014 6:39:57 AM
OrganizationId                                     :
Id                                                 : EXCH1
OriginatingServer                                  : DC1.domain.local
ObjectState                                        : Unchanged

There is no change with the PRX2 error.  In addition I found this:

The InternalDNSServers property specifies the list of internal DNS servers that the server uses to resolve a domain. You must set the value of theInternalDNSAdapterEnabled property to false to use the list of servers in the InternalDNSServers property. If the InternalDNSAdapterEnabled property is true, the DNS settings of the network adapter identified by the InternalDNSAdapterGuid property are used instead.

InternalDNSAdapterEnabled is set to true.  In additional the External DNS servers entry is empty.

• Edited by Dynamic Computer Thursday, January 29, 2015 5:28 PM

Hi ,

1.Does the ip address 192.168.1.1 belongs to your domain controller with DNS? If yes then it is ok.

2.Same time in ecp also please try to have the same ip address on the internal dns lookup available on the mailbox servers .

3.On the exchange servers nic just check the same ip address is assigned on nic card's preferred dns server .

4.Please remove the existing host file entries on the exchange server  and flush the dns cache by using the below mentioned command 

ipconfig /flushdns

5.Then check the name resolution part in the exchange servers by using the nslookup commands.

6.Finally restart the Microsoft exchange transport service and Microsoft exchange front end service and then check the same issue is persisting or not.

1. DC servers set 192.168.1.1 and 1.8

2. Both set in ECP

3. Same set on NIC

4 Removed entries, flush dns

5. Name resolution is working fine.

6. Restarted both

No change, still getting the error.

• Edited by Dynamic Computer Thursday, January 29, 2015 6:45 PM

Hi ,

Have you tried to telnet the exchange server by logging in to the same server ?

I'm telneting from the DC. 

I will try directly from the server the next time it happens.

Hi ,

One more thing i need to clarify from your end .

where the below mentioned error is appearing ? is it appearing on the exchange server receive connectors logs or else on any other servers or clients machines which is trying to send emails ?

Error : 451 4.7.1 Temporary server error. Please try again later PRX2

I only see this when I use telnet directly to the server, or in the logs of my hosted MTA.

I have SMTP logging enabled, but I don't know how to check it for the receive connector.

Hi ,

I hope you would be having the MTA to receive emails from the internet .If so just have the local host entry for the problematic exchange server on the host file in MTA.

x.x.x.x  cas server FQDN

I didn't mean to mislead you, it's not an Exchange MTA.

We use GFI Max mail filtering service.  If it gets the PRX2 error it queues the mail until it's available.  Otherwise the mail would have bounced back to the sender.

The CAS server in this case is all on the same box.

• Edited by Dynamic Computer Thursday, January 29, 2015 7:39 PM

Affirmative.  If I telnet from the Exchange server to itself I also get the error.

Hi ,

Thanks for the reply.

Alright , how the smtp configuration was done on the MTA .Does it routes all the smtp traffic by using the ip address of the exchange or else by using the FQDN of the exchange server ?

How many exchange boxes in your environment? 

In case if you have only one box then on that server how many network cards are available ?

Yes it routes by IP address. (don't forget it's also happening locally)

Only one exchange box.

The server has two nics.  Only one in use.   In addition, I'm also running hyper-v, so the phsical nic 1 in use, but the network config is running on VEthernet-Virtual Switch.

• Edited by Dynamic Computer Thursday, January 29, 2015 7:59 PM

Hi ,

Alright on the exchange server you are having two nics.

1.Please disable or remove the one which is not in use .

2.Then make sure the active nic card is having the first preference on the bindings.

3.start---->Run---->ncpa.cpl------->advanced ------>adapter and bindings------->make sure the active Nic card is on the top.

4.Then on the provider order option make sure the Microsoft windows network is on the top.

5.Then the check MTA and same server is generating such kind of error logs.

Hi ,

Is is there is any update from your side ?