Category Archives: Exchange

Exchange

Install Office Online Server 2016

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In Exchange 2013 you could use the Office Web Apps server in combination with Exchange server to view attachments online, without having to download these attachments first to the local workstation. Exchange 2016 is the successor of Exchange 2013, Office Online Server (OOS) 2016 is the successor of Office Web Apps 2013.

For an optimal user experience in Outlook on the Web you want an Outlook Online Server to view attachments online. Instead of downloading the attachment to your client workstation (not ideal when working on a non-trusted workstation) you can view it in your browser, and your browser will show something like this:

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So how does this work?

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Exchange

Exchange 2013 CU14 Content Indexing failed

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There have been reports about Exchange 2013 CU14 where Content Indexing failed. I’ve heard about CI failing for some Mailbox databases, Mailbox databases containing Public Folder Mailboxes, but also reports about Exchange 2013 Cu14 servers where CI fails for all Mailbox databases.

In the Event Viewer you can find error messages like:

Watson report about to be sent for process id: 28160, with parameters: E12IIS, c-RTL-AMD64, 15.00.1236.003, M.E.Search.Service, M.E.Data.Directory, M.E.D.D.ScopeSet.GetOrgWideDefaultScopeSet, System.ArgumentNullException, 301, 15.00.1236.000.
ErrorReportingEnabled: False

You can find an extended thread on the Microsoft forums as well: Exchnage 2013 CU 14 Database Indexing failed.

The issue is confirmed by Microsoft and Microsoft is working on a fix for this. At this moment it is unknown whether Microsoft will release an Interim Update (IU) or that it will be made available in CU15.

For now my recommendation would be to NOT INSTALL EXCHANGE 2013 CU14 at all.

Update October 27. If you unfortunately run into this issue after installing Exchange 2013 CU14 there’s no other solution then to install Exchange 2013 CU13 and move all your Mailboxes to this server. I cannot call this a fix or workaround, it’s an ugly fallback scenario.

ps. I’ve heard rumors that this issue also appears in Exchange 2016 CU3 but I cannot confirm if this is the case. If you are planning to deploy Exchange 2016 CU3 I would recommend to thoroughly test CU3 before putting it into production.

Exchange

ITDev Connections 2016 Las Vegas

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From October 10 until October 13 the annual IT/Dev Connection was held in the Aria Resort and Casino in Las Vegas, for the 15th time this year.

IT/Dev Connection is a relatively small tech conference with approx. 1000 ~ 1250 attendees (my guess). Because of this size the event is very accessible, attendees can approach speakers, vendors and sponsors easily without being too crowded. It happens regularly that a speaker is walking through the hallway or having lunch at the venue, and it being approached by attendees, this makes an event like this much fun, both for speakers as well as attendees.

The event has a strong Microsoft technology focus although you can see some other sessions as well like sessions about Docker or Amazon Web Services for example. The good thing about this event is that it is an event about Microsoft technology, not organized by Microsoft and sessions are presented by non-Microsoft employees so you get plenty of real world scenarios instead of the marketing talk you typically get at Ignite. Even better, this year there weren’t even keynote sessions since they contain too much marketing blahblah J

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Exchange

SenderID, SPF, DKIM and DMARC in Exchange 2016 – Part III

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In the previous two blog posts I have discussed SPF and DKIM as a way of validating the authenticity of email messages. SPF is using an SPF record in public DNS where all legitimate outbound SMTP servers for a domain are listed. A receiving SMTP server can check this DNS record to make sure the sending mail server is allowed to send email messages on behalf of the user or his organization.

DKIM is about signing and verifying header information in email messages. A sending mail server can digitally sign messages, using a private key that’s only available to the sending mail server. The receiving mail server checks the public key in DNS to verify the signed information in the email message. Since the private key is only available to the sending organization’s mail servers, the receiving mail server knows that it’s a legitimate mail server, and thus a legitimate email message.

As a reminder, my test environment is configured as follows:

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There’s an Exchange 2016 CU2 Mailbox server hosting several Mailboxes, and there’s an Exchange 2016 CU2 Edge Transport server. Using Edge Synchronization all inbound and outbound SMTP traffic is handled by the Edge Transport server.

In the previous two blog posts an SPF record was created and implemented, and DKIM including a DKIM signing module on the Edge Transport server was implemented and functioning correctly.

This last blog in a series of three discusses DMARC, which is built on top of SPF and DKIM. Continue reading SenderID, SPF, DKIM and DMARC in Exchange 2016 – Part III →

Exchange

SenderID, SPF, DKIM and DMARC in Exchange 2016 – Part II

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In the previous blogpost I have been discussing how SPF works and how it uses public DNS to validate the authenticity of the sending SMTP servers. When SPF is implemented correctly a receiving mail server can validate is the sending mail server is allowed to send email on behalf of the sender or his organization.

In this blogpost I will discuss DKIM signing as an additional (and more complicated, and more difficult to spoof) step in email validation.

As a quick reminder, here’s how my lab environment looks like:

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There’s an Exchange 2016 CU2 Mailbox server hosting several Mailboxes, and there’s an Exchange 2016 CU2 Edge Transport server. An Edge synchronization will make sure that all inbound and outbound SMTP traffic is handled by the Edge Transport server.

In my previous blogpost an SPF record was created and implemented with the following value:

v=spf1 a:smtphost.exchangelabs.nl ~all

so receiving mail servers can validate that my Edge Transport server is allowed to send email on my behalf, and when mail is originating from another mail server it might well be a spoofed message.

But for now let’s continue with DKIM. Continue reading SenderID, SPF, DKIM and DMARC in Exchange 2016 – Part II →