Skip to main content

Displaying all the Message Size limits via Script

Message Size limits in Exchange can be set at a number of different levels to give you the flexibility that we as IT people yearn for. This flexibility does come at a cost if you have to answer that quick question about what limits you actually have in your Exchange Org. If you want to work out what the effective message size limit was for one particular user via the GUI you would first have to check

Global Setting under Message Delivery
The Setting on Each Connector the mail could flow though
The Setting on Each of the SMTP Virtual Servers mail could flow though
The Setting on the Actual user account

(This is all documented in Q322679 )

So what I’ve put together is a script that queries all these setting from active directory and outputs the results to the console. The Script logic is pretty simple if queries each of the different objects types in the configuration partition and then accesses the limit property if they have been set and display it back to console. The first query hits the Global settings the second returns all the connector the third returns the virtual servers and the last 2 query looks for all the users that have had individual message size limit configured. These last two queries may look a bit odd but by default the message size limits on a user account would not be set so doing a query where (delivContLength=*) will only return those account where this property has been set.

One thing to remember here is this shows all the native places where message limits may have been configured a lot of third party software such a AV/SPAM/Content-filtering application may also implement this functionality.

I’ve put a downloadable copy of the script here the code looks like

set conn = createobject("ADODB.Connection")
set com = createobject("ADODB.Command")
Set iAdRootDSE = GetObject("LDAP://RootDSE")
strNameingContext = iAdRootDSE.Get("configurationNamingContext")
strDefNamingContext = iAdRootDSE.Get("defaultNamingContext")
Conn.Provider = "ADsDSOObject"
Conn.Open "ADs Provider"
gsQuery = "<LDAP://" & strNameingContext & ">;(objectCategory=msExchMessageDeliveryConfig);name,distinguishedName;subtree"
Com.ActiveConnection = Conn
Com.CommandText = gsQuery
Set Rs = Com.Execute
Wscript.echo "Global Settings - Message Delivery Properties"
Wscript.echo
While Not Rs.EOF
strconfcont = "LDAP://" & rs.fields("distinguishedName")
set ccConfig = getobject(strconfcont)
wscript.echo "Sending Message Size Limit: " & ccConfig.submissionContLength & "
KB"
wscript.echo "Recieving Message Size Limit: " & ccConfig.delivContLength & " KB"
wscript.echo "Recipient Limits: " & ccConfig.msExchRecipLimit
rs.movenext
wend
Wscript.echo
Wscript.echo "Connector Settings"
wscript.echo
vsQuery = "<LDAP://" & strNameingContext &
">;(objectCategory=msExchRoutingSMTPConnector);name,distinguishedName;subtree"
Com.ActiveConnection = Conn
Com.CommandText = vsQuery
Set Rs = Com.Execute
While Not Rs.EOF
strconnect = "LDAP://" & rs.fields("distinguishedName")
set cnCconnect = getobject(strconnect)
wscript.echo "Connector Name:" & cnCconnect.cn
wscript.echo "Max Message Size Limit:" & cnCconnect.delivContLength & " KB"
wscript.echo
rs.movenext
wend
Wscript.echo
Wscript.echo "SMTP Virtual Server Settings"
wscript.echo
vsQuery = "<LDAP://" & strNameingContext &
">;(objectCategory=protocolCfgSMTPServer);name,distinguishedName;subtree"
Com.ActiveConnection = Conn
Com.CommandText = vsQuery
Set Rs = Com.Execute
While Not Rs.EOF
strstmsrv = "LDAP://" & rs.fields("distinguishedName")
set svsSmtpserver = getobject(strstmsrv)
wscript.echo "ServerName:" &
mid(svsSmtpserver.distinguishedName,instr(svsSmtpserver.distinguishedName,"CN=Protocols,")+16,instr(svsSmtpserver.distinguishedName,",CN=Servers")-(instr(svsSmtpserver.distinguishedName,"CN=Protocols,")+16))
wscript.echo "Virtual Server Name:" & svsSmtpserver.adminDisplayName
wscript.echo "Max Message Size Limit:" &
svsSmtpserver.msExchSmtpMaxMessageSize/1024 & " KB"
wscript.echo "Recipient Limits:" & svsSmtpserver.msExchSmtpMaxRecipients
wscript.echo
rs.movenext
wend
Wscript.echo
Wscript.echo "Users with Sending Limits"
wscript.echo
srquery = "<LDAP://" & strDefNamingContext &
">;(&(&(objectCategory=Person)(objectclass=user)(submissionContLength=*)));name,displayname,distinguishedName
,submissionContLength;subtree"
Com.ActiveConnection = Conn
Com.CommandText = srquery
Set Rs = Com.Execute
While Not Rs.EOF
wscript.echo "User:" & rs.fields("displayname")
wscript.echo "Sending Message Size Limit:" & rs.fields("submissionContLength") &
" KB"
wscript.echo
rs.movenext
wend
Wscript.echo
Wscript.echo "Users with Receiving Limits"
wscript.echo
srquery = "<LDAP://" & strDefNamingContext &
">;(&(&(objectCategory=Person)(objectclass=user)(delivContLength=*)));name,displayname,distinguishedName,delivContLength;subtree"
Com.ActiveConnection = Conn
Com.CommandText = srquery
Set Rs = Com.Execute
While Not Rs.EOF
wscript.echo "User:" & rs.fields("displayname")
wscript.echo "Receiving Message Size Limit:" & rs.fields("delivContLength") & "
KB"
wscript.echo
rs.movenext
wend

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-
Read more

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
Read more

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
Read more
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.