Category Archives: Exchange 2013

Exchange Hybrid lockdown to O365 IP’s only

With the recent Exchange vulnerabilities comes a moment to reflect on further ways to reduce the attach surface of Exchange Servers.

Many organizations still host an Exchange Server solely to maintain a hybrid connectivity link to Office 365. The server therefore has to be publicly accessible, but only to Microsoft. Often this is not the case.

If you don’t have a professional firewall to restrict traffic to only that coming from Microsoft, you can also do so at the IIS level. Microsoft publishes a list of IP’s they use here:

https://endpoints.office.com/endpoints/worldwide

We can then take that source address data and add each IP in it to an Allow entry at the global level in IIS using PowerShell:

[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Web")
$res = [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls -bor [Net.SecurityProtocolType]::Tls11 -bor [Net.SecurityProtocolType]::Tls12
$allRanges = @("fe80::946:a60c:3d5:ec11%3","127.0.0.1","::1")
$o365IPs = Invoke-RestMethod -Method GET -UseBasicParsing -Uri "https://endpoints.office.com/endpoints/worldwide?clientrequestid=b10c5ed1-bad1-445f-b386-b919946339a7" 
$o365IPs | % {$_.ips | %{if($allRanges -notcontains $_){$allRanges += $_}}}
$allRanges | % {
    if($_.IndexOf("/")){
        $payLoad = @{ipAddress=$_.Split("/")[0];allowed="true";subnetMask=$(([ipaddress]([double]4294967296-(1-shl32-$($_.Split("/")[1])))).IPAddressToString);}
    }else{
        $payLoad = @{ipAddress=$_;allowed="true";}
    }
    try{$null = Add-WebConfigurationProperty  -Filter 'system.webServer/security/ipSecurity' -PSPath "IIS:\" -Name "." -Value $payLoad -ErrorAction SilentlyContinue}catch{$Null}
}

Finally, set IIS’s IP Address and Domain restriction mode to Deny:

note: you can add additional ranges to $allRanges as needed for internal management, monitoring etc.

Public Folder to Office 365 Groups Migration Script

Earlier, I wrote on a new technet article that details migration to Office 365 groups from on prem public folders. Actually walking through that I noticed some inconveniences I figured I could improve on with a script. The main one being that the endpoint in Office 365 only supports a single Public Folder, excluding child folders.

So I wrote up a script (with resume support) that will map your Public Folders to O365 Groups and migrate them in as many batches as are required, fully automated.

You’ll end up with a nice csv file with all the details. Note:

  1. this script expects you to know what you’re doing!
  2. only tested with Exchange 2010 as source
  3. everything on prem is left untouched
  4. groups are not mail enabled, and security settings are not copied
  5. contacts are not copied
  6. make sure you read the code/in-script instructions between line 1 and line 48, and then if you’re curious, from line 71720

https://gitlab.com/Lieben/assortedFunctions/blob/master/archivePublicFoldersToOffice365Groups.ps1

update 05/01: improved the connection status check + reconnect for remote ExO and fixed report file path auto generation

update 11/01: moved everything to start-job so exchange sessions are always isolated (no prompting after 1-2 days) and added total migration overview display 

update 25/01: exported the remote exchange module and added it as inline code with a modification so it won’t prompt for credentials, nothing else seems to otherwise prevent such prompts. This means the module may not match Microsoft’s if they update Exchange Online. Let me know if that causes issues for you or re-create it yourself with export-pssession and replace.

Migrating Public Folders to Office 365 Groups

Recently, I stumbled upon an article detailing how to migrate on-premises (or online) Public Folders to Office 365 Groups

Of course I had to try that out asap 🙂 I used an older script to make a report of my on prem public folders to pick one below 50GB.

It was mostly a breeze and the interface of Office 365 groups allows users to easily search and administer their old Public Folders. We purposely only use them for archive access, where the IM team manages access to the groups holding PF data. I can really recommend this strategy, especially if you can easily split them up in under 50GB sized groups.

I did have one slight error you may run into:

“MigrationTransientException: Couldn‎’t find a request that matches the information provided. Reason: No such request exists in the specified index. –> Couldn‎’t find a request that matches the information provided. Reason: No such request exists in the specified index. “

Reason for this: The source public folder path is incorrect, make sure your CSV is mapped correctly or your batch will spin forever (or at least longer than I had patience), never completing.

 

 

Exchange 2010 backend with 2013 frontend proxy something has gone wrong error

At a customer site users were experiencing “:-( Something went wrong” errors in OWA (2013). The RPC endpoint was also broken, blocking a migration to Office 365.

Initial checks showed a few errors on the 2013 frontend server:


[Eas] Marking ClientAccess 2010 server NLEX01.domain.local (https://nlex01.domain.local/Microsoft-Server-ActiveSync) as unhealthy due to exception: System.Net.WebException: The remote server returned an error: (503) Server Unavailable.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.Exchange.HttpProxy.ProtocolPingStrategyBase.Ping(Uri url)

[Autodiscover] Marking ClientAccess 2010 server NLEX01.domain.local (https://nlex01.domain.local/Autodiscover) as unhealthy due to exception: System.Net.WebException: The remote server returned an error: (503) Server Unavailable.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.Exchange.HttpProxy.ProtocolPingStrategyBase.Ping(Uri url)

[RpcHttp] Marking ClientAccess 2010 server NLEX01.domain.local (https://nlex01.domain.local/rpc/rpcproxy.dll) as unhealthy due to exception: System.Net.WebException: The remote server returned an error: (503) Server Unavailable.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.Exchange.HttpProxy.ProtocolPingStrategyBase.Ping(Uri url)

[Owa] Marking ClientAccess 2010 server NLEX01.domain.local (https://nlex01.domain.local/owa) as unhealthy due to exception: System.Net.WebException: The remote server returned an error: (503) Server Unavailable.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.Exchange.HttpProxy.ProtocolPingStrategyBase.Ping(Uri url)

The issue ended up being twofold;

  1. somehow the SCCM client on the Exchange backend had replaced the local server certificate that IIS uses, this certificate wasn’t accepted by the frontend server
  2. for some reason NTLM (Windows) Authentication was switched off on the Virtual Directories on the backend machine.

Quick overview of all unique email domains in use under a certain OU

We wanted an overview of which domains our users were using in a certain country (Netherlands in this case). So, a simple Powershell snippet that counts all unique domains it encounters in the ProxyAddresses field of all users under a certain OU.

Note that if you have set contacts / forwarders, some domains that appear may not actually be accepted domains in your exchange organization.


#Author: Jos Lieben (OGD)
#Date: 13-06-2016
#Script help: www.liebensraum.nl
#Purpose: retrieve all unique domains in use under a specific OU and count them
#Requirements:
#active directory PS module
########

ipmo activedirectory

$users = get-aduser -Filter * -Properties * -SearchBase "OU=Netherlands,OU=Countries,DC=lieben,DC=nu" -SearchScope SubTree

$domains = @{}
foreach($user in $users){

$emails = $user.ProxyAddresses
foreach($email in $emails){
$domain = $email.Split("@")[1]
if($domain){
$domains[$domain] += 1
}
}

}

Write-Output $domains