Rename filenames containing strange characters with PowerShell

Recently I had a computer with tons of file on it which I had to backup and upload to OneDrive for Business (OdfB). For some unknown reason there were lots of file that had the HTML representation of a space character in it (%20), there were also filenames containing a # character.

Needless to say, the OdfB client didn’t like it, and kept complaining about not being able to upload files, it wanted to try again and again…. Renaming these files (in hundreds of directories) was not something I fancied, but this is great for PowerShell to figure out.

To find all files that contained the %20 in it I used the following command:

Dir -Recurse | Where-Object {$_.Name -like "*%20*" }

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Now it’s just a matter of renaming the “%20” with another character, for example an underscore character “_”, like this:

Dir -Recurse | Where-Object {$_.Name -like "*%20*" } | Rename-Item -NewName { $_.Name -replace "%20","_" }

Et voila, all “%20” characters are now removed from the filenames, and ready to be uploaded to OneDrive for Business

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

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

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

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

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

SenderID has been used in Exchange as a means for anti-spam for quite some time, as far as I can remember this was first used in Exchange 2010. Related to SenderID is SPF (Sender Policy Framework). SPF looks like SenderID functionality, but it differs in the way how it checks email messages.

Both use public DNS records with TXT records where information is stored regarding the sending SMTP server, and this information is used by the receiving (Exchange) server to validate if the sending server is allowed to send email on behalf of the sender.

Getting more popular for fighting spam are DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting & Conformance). Just like SenderID and SPF, these solutions use public DNS for additional information as well, but since encryption is used most Exchange admin have some doubts about the complexity of DKIM and DMARC.

In the upcoming blogpost I’ll discuss SPF, DKIM and DMARC as implemented in my lab environment which looks like this:

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There’s an Exchange 2016 CU2 Mailbox server hosting several Mailboxes. The server is accessible via webmail.exchangelabs.nl and autodiscover.exchangelabs.nl (same IP address, behind a Kemp LM3600 load balancer) and configured with a Digicert UC certificate.

In addition to this there’s an Exchange 2016 CU2 Edge Transport server with FQDN smtphost.exchangelabs.nl. Besides the regular A and MX record, the IP address is also configured in Reverse DNS. The Edge Transport server is also behind a Kemp LM3600 load balancer, and it has a Digicert SSL Certificate with the same domain name. There’s an Edge Synchronization configured between the Mailbox server and the Edge Transport server, and all inbound and outbound mail is handled by the Edge Transport server. Continue reading SenderID, SPF, DKIM and DMARC in Exchange 2016 – Part I

POP3, IMAP4, Get-Service and Startup Type

When installing lots of Exchange servers, automation with PowerShell scripting can be very useful. This will ensure you get a consistent platform, and it reduces the chance of errors and misconfiguration.

For a customer I had to deploy 38 Exchange 2013 servers, and they were using POP3 and IMAP4 as well, so these services need to be installed on all Exchange 2013 servers.

By default, POP3 and IMAP4 are not running on an Exchange 2013 server, and the service Startup Type is set to Manual.

You can change the startup type to automatic using the Services MMC snap-in, but for 38 Exchange 2013 servers this isn’t funny anymore.

You can use the Get-Service cmdlet in Windows to retrieve information regarding Windows services, for example:

Get-Service –ServiceName MSExchangePOP3

Or add the Format-List option to get more detailed information:

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You can use the –ComputerName option to retrieve similar information from another server:

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There’s all kind of interesting information here, but the most important thing, the Startup Type information is missing here.

To retrieve the Startup Type information you can use the Get-WmiObjectcmdlet and filter on the service name, for example:

Get-WmiObject -Class Win32_Service -Property StartMode -Filter "Name='MSExchangePOP3'"

Please note the single and double quotes in the Filter option!

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Again, you can use the –ComputerName option to retrieve this information from another server.

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Note. On an Exchange 2013 (and Exchange 2016) server POP3 and IMAP4 are actually two services. There’s the CAS component (MSExchangePOP3) and the Mailbox server component (MSExchangePOP3BE). These services need to changed independently. The same is true for the IMAP4 service.

You can write a small script to create an overview of all Exchange servers with the Startup Type of all POP3 service, this will look something like:

$Servers = Get-ExchangeServer
ForEach ($Server in $Servers){
$Computer = $Server.Name
$Object = Get-WmiObject –Class Win32_Service –Property StartMode –Filter “Name=’MSExchangePOP3’”
Write-Host $Computer,$Object.StartMode
}

You can change the Startup Type of the POP3 service using the Set-Service command:

Set-Service –ServiceName MSExchangePOP3 –StartupType Automatic

And you can use the-ComputerName to change the Startup Type of a service running on another Server:

Set-Service –ServiceName MSExchangePOP3 –StartupType Automatic –ComputerName EXCH02

More information:

Use PowerShell to Find Non-Starting Automatic Services – https://blogs.technet.microsoft.com/heyscriptingguy/2012/12/18/use-powershell-to-find-non-starting-automatic-services/

Get-Service – https://technet.microsoft.com/en-us/library/hh849804.aspx

Set-Service – https://technet.microsoft.com/en-us/library/hh849849.aspx

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