Skip to main content

Disabling and Enabling POP3 and IMAP protocol settings via ADSI

  When you install Exchange and create all your mailboxes by default every mailbox will have POP3,IMAP and HTTP protocols enabled. Good practice is if you don't want people to use these protocols is just disable the protocols on the server which makes the user account settings redundant. But this is not always possible and sometimes you need to leave POP3 and IMAP access enabled for some applications or clients. So to stop people using POP3 and IMAP it can be a good idea to disable that protocol on their Active Directory user account.

  To do this via ADSI is not that hard if you keep the following things in mind. The property that controls both these setting is the protocolSettings attribute of the User object. This is a mutli-valued property which also holds the setting for HTTP (OWA Access) as well.  By default this property will be blank meaning everything is enabled. Once you disable a protocol a value will get written for that protocol into the property. If you then re-enable the protocol this entry is not deleted rather one bit in the existing property is flipped. For example when I disable IMAP the following gets written into this property.

IMAP4§0§1§4§ISO-8859-1§0§1§0§0  (note because I'm an Aussie we use ISO character sets)

When you re-enable IMAP it just flips the first bit after the protocol IMAP4§0 from 0 to 1 eg

IMAP4§1§1§4§ISO-8859-1§0§1§0§0

So armed with this information to disable pop3 and imap on a mailbox with ADSI, (taking into account nothing has been set for HTTP because this will overwrite that property) you could use the following code (make sure you change the character set to whatever you use)

qstring = "LDAP://CN=USER,OU=wherver,DC=domain,DC=com"
set objUser = GetObject(qstring)
objUser.PutEx 2, "protocolSettings",ARRAY("POP3§0§1§4§ISO-8859-1§0§§§","IMAP4§0§1§4§ISO-8859-1§0§1§0§0")
objUser.setinfo
 
Flipping it back is a matter of using the same code with the reverse bits

qstring = "LDAP://CN=USER,OU=wherver,DC=domain,DC=com"
set objUser = GetObject(qstring)
objUser.PutEx 2, "protocolSettings",ARRAY("POP3§1§1§4§ISO-8859-1§0§§§","IMAP4§1§1§4§ISO-8859-1§0§1§0§0")
objUser.setinfo



Popular posts from this blog

Testing and Sending email via SMTP using Opportunistic TLS and oAuth in Office365 with PowerShell

As well as EWS and Remote PowerShell (RPS) other mail protocols POP3, IMAP and SMTP have had OAuth authentication enabled in Exchange Online (Official announcement here ). A while ago I created  this script that used Opportunistic TLS to perform a Telnet style test against a SMTP server using SMTP AUTH. Now that oAuth authentication has been enabled in office365 I've updated this script to be able to use oAuth instead of SMTP Auth to test against Office365. I've also included a function to actually send a Message. Token Acquisition  To Send a Mail using oAuth you first need to get an Access token from Azure AD there are plenty of ways of doing this in PowerShell. You could use a library like MSAL or ADAL (just google your favoured method) or use a library less approach which I've included with this script . Whatever way you do this you need to make sure that your application registration  https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-register-

How to test SMTP using Opportunistic TLS with Powershell and grab the public certificate a SMTP server is using

Most email services these day employ Opportunistic TLS when trying to send Messages which means that wherever possible the Messages will be encrypted rather then the plain text legacy of SMTP.  This method was defined in RFC 3207 "SMTP Service Extension for Secure SMTP over Transport Layer Security" and  there's a quite a good explanation of Opportunistic TLS on Wikipedia  https://en.wikipedia.org/wiki/Opportunistic_TLS .  This is used for both Server to Server (eg MTA to MTA) and Client to server (Eg a Message client like Outlook which acts as a MSA) the later being generally Authenticated. Basically it allows you to have a normal plain text SMTP conversation that is then upgraded to TLS using the STARTTLS verb. Not all servers will support this verb so if its not supported then a message is just sent as Plain text. TLS relies on PKI certificates and the administrative issue s that come around certificate management like expired certificates which is why I wrote th

The MailboxConcurrency limit and using Batching in the Microsoft Graph API

If your getting an error such as Application is over its MailboxConcurrency limit while using the Microsoft Graph API this post may help you understand why. Background   The Mailbox  concurrency limit when your using the Graph API is 4 as per https://docs.microsoft.com/en-us/graph/throttling#outlook-service-limits . This is evaluated for each app ID and mailbox combination so this means you can have different apps running under the same credentials and the poor behavior of one won't cause the other to be throttled. If you compared that to EWS you could have up to 27 concurrent connections but they are shared across all apps on a first come first served basis. Batching Batching in the Graph API is a way of combining multiple requests into a single HTTP request. Batching in the Exchange Mail API's EWS and MAPI has been around for a long time and its common, for email Apps to process large numbers of smaller items for a variety of reasons.  Batching in the Graph is limited to a m
All sample scripts and source code is provided by for illustrative purposes only. All examples are untested in different environments and therefore, I cannot guarantee or imply reliability, serviceability, or function of these programs.

All code contained herein is provided to you "AS IS" without any warranties of any kind. The implied warranties of non-infringement, merchantability and fitness for a particular purpose are expressly disclaimed.