Replace Mail Relays with Exchange Online

Executive Summary

Yale intends to decommission the Mail Relay machines and replace their function with the Exchange Online component of Azure/O365. The Mail Relays are configured with data from the Email Alias system.

Yale University advertises to the world (through MX records in the DNS system) that the email domain “@yale.edu” is managed by a group of computers we call the Mail Relays. The world sends all “@yale.edu” mail to the Mail Relays and they forward the mail to the appropriate other system that actually has mailboxes in which to deposit the mail.

The Mail Relays process mail through a SPAM/security scan. It then looks up the destination mail address in tables created from the Yale Email Alias table. If it finds a match, it forwards the mail to the account identified in the MAILBOX field of the matching Alias entry. There are three possibilities:

1. A MAILBOX value ending in “@connect.yale.edu” (or any other domain associated with O365 mail) is sent to the Microsoft Exchange Online service.

2. A MAILBOX value ending in “@bulldogs.yale.edu' is sent to Google.

3. Any other MAILBOX value is the DNS name of a computer service. The service may provide email mailboxes for users, or it may read and process the mail (when Service Now turns mail to specific destinations into tickets), or it may forward the mail to a different address.

If we replace the Mail Relays with Exchange Online, then we change the DNS server MX record so that the “@yale.edu” domain goes directly to Exchange. We do none of the preprocessing done by the Relays and send all the mail to destination 1 in the previous list.

To make this work, we require that Exchange Online be configured to do three things:

• While Exchange has always been configured with Primary Email Aliases for O365 accounts, it has not been configured with all the secondary aliases. Sometimes Exchange depended on the Mail Relays to translate Aliases it did not know into specific accounts. We must add all Aliases to the Exchange configuration.

• Exchange was originally configured with only O365 accounts. A year ago we added the Primary Email Aliases of students with an Eliapps account. We need to add in the secondary aliases.

• Every other Email Alias not configured in the previous two steps has to be configured to Exchange Online as a Contact object in AD. The Alias Name is a ProxyAddress and the MAILBOX is a Target Address.

To be sure everything is configured correctly, the following things must be true:

1. Every Email Alias of a personal O365 mail account must be in the ProxyAddresses list of the AD object associated with that account.

2. Every Email Alias of an Eliapps or other non-O365 mail account must be in the ProxyAddresses list of some AD object (User or Contact) whose TargetAddress is equal to the MAILBOX value of the Alias.

3. A given Alias must be unique in the AD (it must be in only one ProxyAddresses list of one object).

4. Every AD object (User or Contact) involved in Mail Routing must have a unique Mail Box value, which is the Primary Alias Name of User objects and the first ProxyAddress of Contacts.

We can run through the Email Alias table and make sure that every row is associated with some object and that the fields match up. However, fixing errors that exist in the Alias Table or existing AD objects is an ongoing function. Most of these errors are not related to the Mail Relay function and need not be fixed in order to retire the Mail Relays.

Exchange Online Configuration

The only way to know for sure if a user has an Exchange mail account or if an email address is known to it is to ask Exchange Online directly. The easiest way to do this is with Powershell.

Exchange has what it calls MailRecipients. There are three primary types of Recipients: O365 personal mail accounts (called a UserMailbox), external mail accounts (mostly Eliapps) that Exchange knows about, and “resources” like SharedMailboxes and Distribution Lists.

It turns out that anyone with a Netid can download code and ask Exchange to provide information on all Recpients:

$recipients=get-exorecipient -ResultSize unlimited -Properties ExternalEmailAddress

If you are patient, you will get back something around 106126 objects. There is an UserMailbox object for every Netid who has a personal O365 mail account. There are a set of more specific object types for the native Exchange objects created by Exchange administrators that receive mail but are not people:

MailUniversalSecurityGroup
SharedMailbox
GroupMailbox
GuestMailUser
RoomMailbox
MailUniversalDistributionGroup
EquipmentMailbox
SchedulingMailbox
DynamicDistributionGroup
DiscoveryMailbox
PublicFolder
TeamMailbox

Eliapps and other external (non-Exchange) mail addresses can be configured in a User object (a MailUser) or else a MailContact. Exchange doesn’t really care if you put external mail accounts in Users or Contacts, but a Yale we have decided to put aliases to personal student Eliapps mail accounts in the student’s User object, and put everything else in a Contact.

IAM has responsibility for User objects, whether the User has an O365 mail account or an Eliapps mail account. This information is affected by changes to the personal information that IAM manages. For example, when a student changes a First or Last name, this frequently changes the Primary Email Alias, and that in turn changes both the mail routing functions we are talking about here, but also the login values like UserPrincipalName presented by the user to get access to his O365 applications.

Contacts are generally created for accounts that are manually created on request. Sometimes they are associated with a specific identity of a real person known to IAM, but who for business reasons chooses not to use either the standard O365 or Eliapps mail systems. Sometimes there are special security requirements that require special accounts. Such a person will still have a Netid and an AD User object and a non-Mail O365 account. The Primary Email Alias will create a UPN and will be the “mail” attribute of the AD User object, so subject to privacy the user’s Email can appear in the directory. However, the routing information will be in a separate Contact object and we expect that the Contact object will be updated manually when the manually created Email account is manually changed. If these accounts are important enough to have their own mail system, IAM cannot assume they are subject to the ordinary behavior of student and regular staff accounts.

There is the AD Name, the Exchange Name, and the Yale Name

Unfortunately, the same thing has different names in different contexts.

Contacts are created for Aliases that are not Exchange accounts and are not Primary Aliases of Eliapps students. It is not necessary to say what these accounts are, but in case you want to know, they are mostly:

• Eliapps accounts of people who also have an O365 mail account. These are mostly ITS people.

• Elilists (a type of mailing list managed by Eliapps instead of Exchange)

• Student groups (example: yale.spizzwinks@bulldogs.yale.edu)

• Departmental shared mailboxes (example: thechildlab@bulldogs.yale.edu)

• The 111 aliases of servicenow@bulldogs.yale.edu

• Mail for specific department servers (invest.yale.edu, aya.yale.edu)

• Everything else. Sometimes this is recognizable junk left over from machines that have not existed since 1995 (gopher.cis.yale.edu) but it is not necessary to clean this up and that is not part of this project.

Is It Right and Is It Complete

Yale has an Email Alias database table. It has an ALIAS_NAME column and a MAILBOX column. The ALIAS_NAME is unique (it appears only once in the table).

Every ALIAS_NAME has to be configured so that Exchange Online delivers mail to a local mailbox or else forwards mail to the correct external mailbox.

The first rule is that there should not be duplicate ProxyAddresses entries in more than one AD object. At this time, there are some duplicate ProxyAddresses for some SharedMailbox objects, but although incorrect this is not a problem that has to be solved in order to replace the Mail Relays since SharedMailboxes and all the other room and group resources manage by Exchange are already configured and removing the Mail Relays does not affect them. At some time in the future we should fix this.

Currently, if a secondary ALIAS_NAME is associated with an O365 personal mail account (that is, if the MAILBOX value is “netid@connect.yale.edu” or “first.last@connect.yale.edu”) and because of an error in our systems there is no ProxyAddress in the User object for that Netid matching the ALIAS_NAME, then Exchange sends the mail to the Mail Relays who look up the Alias in the table to find the MAILBOX and then send the mail back to Exchange with the MAILBOX information. Exchange delivers the mail correctly today but would not deliver it if the Mail Relays did not correct the configuration error. So we must make sure that all Aliases that match a “@connect.yale.edu” MAILBOX are in the ProxyAddresses list. This requires fixing or replacing the AD Updater process (work in progress now).

Students with a Primary Email Alias whose MAILBOX value ends in “@bulldogs.yale.edu” have an AD User object whose TargetAddress is the MAILBOX value and must have in the ProxyAddresses list all the ALIAS_NAMES that had the same MAILBOX value as the Primary Alias MAILBOX.

Once you remove the previous three cases (Aliases of SharedMailboxes, of Personal O365 accounts, or of Personal Eliapps accounts) then all remaining ALIAS_NAMES must be a ProxyAddress of a Contact whose TargetAddress is the MAILBOX value of that Alias. We could have created a Contact for every Alias (there is no requirement that TargetAddresses be unique) but it is convenient to collect all Aliases of the same MAILBOX in the same Contact.

At this point, every Alias has been mapped, and it should be mapped to its MAILBOX.

Up to this point, we have verified the configuration in terms of the local AD, which is the mechanism we have to configure Exchange Online. We can doublecheck the configuration from the Exchange Online point of view. This gives us a separate validation, but through a Read-Only mechanism. If we find a problem, we have to go back to the AD and figure out how to fix it.

Remember the Powershell command:

$recipients=get-exorecipient -ResultSize unlimited -Properties ExternalEmailAddress

This gives you a set of objects that includes all the recipients (SharedMailboxes, O365 accounts, Eliapps users, and Contacts) from the point of view of Exchange Online. Remember, we configure Local AD, which is then used to configure Azure AD, which is then used to configure Exchange Online. So now we skip to the final end result and see if the stuff we put in at the beginning ended up where we wanted it to be.

Each Recipient object has an EmailAddresses list. Every Email Alias should be found in one EmailAddresses entry of one Recipient object. The advantage of this check is that you don’t have to distinguish different types of users or mail or aliases. Every ALIAS_NAME should match one Recipient and the ExternalEmailAddress should match the MAILBOX value.

AD Management

Exchange Online requires that entries in any ProxyAddresses list must be unique. This process generates them from the ALIAS_NAME column of the Email Alias table which is constrained to be unique.

Because the Azure AD already has to be properly configured for O365 personal and shared mailbox accounts (or Exchange would not be able to deliver mail to these destinations), there is no need to make any changes for Email Alias Table entries that resolve to the “@connect.yale.edu” mail domain or any other domain that is an alias of Exchange itself.

For a year, we have been populating the TargetAddress field of the User object of 15000 current active or new students with an Eliapps mail account. There are approximately 1000 additional User objects for what appear to be former students who still have active mail whose User objects will now be populated.

Previously it was unnecessary to update the TargetAddress when a student changes their name. Technically this is still not necessary (because the old name remains an alias of the Eliapps account) but it seems to be better if this field is updated when the MAILBOX of the Primary Email Alias is changed. In addition, we were not previously adding Secondary Aliases to the ProxyAddresses list but will add them now. It may be unlikely that anyone will receive mail under an old name changed three years ago, but as long as the old name remains in the Alias Table, this project must configure Exchange Online to deliver mail to all currently valid Aliases no matter how unlikely it is that they are actually in use.

Therefore, there is a simple test to verify that the configuration required by this project is complete. Run through all the rows in the Email Alias Table (DIR_ONLINE_INFO). If the MAILBOX is one of the Exchange Online domains, ignore it. Otherwise, look for a ProxyAddresses entry matching the ALIAS_NAME value in some AD User or Contact object. The TargetAddress property of that object must match the MAILBOX value of the Alias.

We cannot preserve the behavior of a handful of personal aliases where a user has created mailboxes with the same name in both O365 and Eliapps and has set the Primary Alias to point to Eliapps. With the Mail Relays, mail sent by O365 users goes to the O365 mailbox and all other mail goes to Eliapps. When the Relays are retired, all mail will go to O365. The old behavior cannot be duplicated, but this configuration violates Yale policy so we will simply inform the affected users before the change.

Fine Tuning

This project has to refine the list of email domains that are inherently associated with Exchange Online. We know that “@expectwithme.org” is actually an O365 alias, but while ayalists.yale.edu is in Exchange, elilists.yale.edu is in Google, and “lists.architecture.yale.edu” is uncertain. This is not just an IAM problem, because Linux Systems has to fix the MX records for each of these domains.

There are data errors in the Alias Table that will generate unnecessary Contacts. It is not necessary to fix them at this time, but if we don’t do it now, there will be no better time in the future.

Source of Problems (History)

Originally Yale did not think of Email as a single topic.

There was the problem of Student Mail, addressed by the Instructional Support group of ITS. Then there was Employee mail decided by the business focused groups. Once a system was selected, there was some involvement by Unix or Windows groups for technical support.

However, SMTP is a service that you could run on any mainframe, Unix, or Windows NT computer. At one point, main departments ran their own mail servers. The original design of the Email Alias system allowed a user to create an Alias that pointed to the computer under there desk. (So many of these machines were compromised by spammers that this became a violation of Yale security policy, but it was too late to change the Alias system).

IAM became involved for three reasons.

• Historically, there was a time when we charged back mail accounts to departments, and IAM inherited the systems that were created for that purpose even after we stopped charging for mail accounts.

• IAM creates basic resources like a Netid and AD object for new students, employees, and sponsored identities. Students and employees automatically get mail accounts, and it was efficient for IAM to create these “birthright mail” accounts when a new identity is created.

• What people think of as the Email Address is also a unique login string (a “principal” name) for the non-mail functions like OneDrive, Google Drive, and Box. IAM has to manage it as a login name and, among other things, lock and unlock it along with the Netid.

However, other groups make changes to Email accounts. The Help Desk changes the Aliases and the Eliapps account when a user changes their name. The current Email support group creates O365 and Eliapps accounts for non-birthright users, and helps to change accounts when someone changes their Yale association.

IAM is involved with Mail, but we did not set the original rules (remember, Instructional Support decided how Eliapps accounts would be named), nor are we involved in all updates. We own the DIR_ONLINE_INFO table of Mail Aliases even though the Help Desk changes the aliases in it, and we know enough about the rest of the mail system to implement this change.

Example of Problems

A student named Johnathan Doe is initially assigned a Primary Alias of “johnathan.doe” and an Eliapps account name of “johnathon.doe@yale.edu” which means the Alias MAILBOX value is “johnathon.doe@bulldogs.yale.edu”. Then he changes his name to “John” and requests his Email get “fixed”.

A new Alias of “john.doe” is created initially as a secondary alias, but it is then promoted to Primary and the old johnathan.doe becomes a Secondary Alias. The same thing happens to the Eliapps account, which is renamed “john.doe@yale.edu” but has an alternate Email address of the old “johnathan.doe@yale.edu”.

If this is done correctly, then both the new Primary “john.doe” and the secondary old “johnathan.doe” Alias Table entries have a MAILBOX of “john.doe@bulldogs.yale.edu”. Then we know that these are two aliases of the same account. However, because both the new and old names are in the Eliapps User Directory, mail does get delivered correctly if someone is sloppy. So frequently enough we get:

Google makes it unreasonably inefficient to query them and determine that “john.doe@yale.edu” and “johanthan.doe@yale.edu” are two names for the same Eliapps account, and we do not maintain a local table that remembers that we renamed the account. So from what information we have locally on which we can build code, there is no way to know that these are two entries for the same account. That means that the Secondary Alias will generate a Contact object. This is not a problem because this user probably only wants the current Primary alias listed in the directory and the only need for the secondary alias to to make sure that any mail for old addresses also gets delivered.

There is an O365 version of this problem that does have to be solved somehow. If John Doe was an O365 user, there are about 150 case of:

If you read through the ADDailyUpdater source code you encounter a long comment beginning with “This is a hack for exchange and this is why...” followed by a long explanation that makes no sense at all. The upshot of this is that for 20 years we have added “first.last@connect.yale.edu” to the ProxyAddresses list for no apparent reason I can understand except to make it possible for a hundred or so Exchange users to have a working but inherently defective pair of MAILBOX values that point to the same O365 account using different strings. Again, the problem here is that you cannot tell they are the same account and have to go in the same User object based only on the values in the Email Alias table. You have to go to the AD and search for the ProxyAddresses to see that both values are ProxyAddresses of the same User object. This is a data error and may have to be fixed because you cannot code around it without wasting too much time.

The Alias Table

ToDo Eventually: Some IAM tools display and operate only on the collection of aliases owned by the same Netid, but to migrate the Mail Relay function to Exchange, all Aliases pointing to a personal mailbox have to be listed in the ProxyAddresses list of the AD User object that owns the O365 mailbox or that points to the Eliapps account. Netid is significant for Primary Aliases, but Secondary aliases should be managed by the MAILBOX they point to and not the Netid that owns them. This will be a change to ODMT.

Shared Mailboxes: The Help Desk and Email Managers create Shared Mailboxes for someone (the “owner”) by a sequence of steps.

They create a Dependent Netid for the owner.

They create an Alias for the shared mailbox, with a topical ALIAS_NAME like “blackhole.astronomy”, a MAILBOX that points to “dependentnetid@connect.yale.edu”, and then for some reason they assign ownership of the alias to the owner of the dependent netid instead of to the dependent netid itself.

Then they create the shared mailbox in Exchange.

Now a decade goes by and the owner leaves or retires without transferring either the Alias or the Dependent Netid to someone else. When his personal mailbox is deprovisioned, we do not know what to do with them and leave them attached to his now disabled User object.

At this point we have violated a bunch of original design points of the system, and various pieces of code do the wrong thing creating duplicate ProxyAddresses and other bad stuff.

To fix it, the Alias should be owned by the Dependent Netid. Then at least we would not be breaking the rules and the various programs would do the right thing. However, since this is a SharedMailbox even though we do a bunch of bad things to AD, the Exchange Online configuration continues to work correctly, so this is not the time to fix this.

Right the First Time: If mail accounts (Birthright and Manual, O365 and Eliapps) are generated with correct AD ProxyAddresses and TargetAddress values, and if they are updated when aliases change or an Eliapps account is renamed, then it should not be necessary to run the “AD Daily Updater” function. It was created to allow sloppy tools to do only part of the work and then go back once a day to fix the mistakes. We can do better than that.

The Mail Relays

Someone sends mail to “john.doe@yale.edu” or “gravitywaveastronomy@yale.edu”. The sending system does a DNS search for an MX type record associated with the name “yale.edu” and gets back the following:

This is a list of the Mail Relay machines (informally known as the “teas”). The mail is sent to one of these machines.

The Mail Relay computer programs are internally configured with files generated from the Alias Table. The program that generates these configuration files looks at each ALIAS_NAME and MAILBOX value. When an incoming Email address ends in “@yale.edu”, then the part in front of “@” must match an ALIAS_NAME in the Alias Table or the mail bounces as undeliverable. If an ALIAS_NAME is matched, then in that row the email domain (the part after “@”) in the MAILBOX value tells the Mail Relay where to forward the mail. The association of mail domain suffix values to the DNS name of one or more server machines is also published as MX records in the DNS system (although the Mail Relays may already have a copy of this data in memory). Looking up the “connect.yale.edu” suffix finds:

while the MX records for “bulldogs.yale.edu” are:

However, the MAILBOX value of an entry in the Alias Table can contain a suffix that is not an MX record. In this case, the suffix is the name of a computer that runs some type of mail server software. Then the relay does an ordinary DNS lookup for the machine and forwards the mail to that computer. The problem of poorly managed mail server software (which could get compromised or abused by SPAM senders) was mostly addressed a decade ago, and we discourage these configurations, but this option was never removed from the Alias system.

Exchange Online

If we replace the Mail Relays with Exchange Online, then the previous step doesn’t happen. We change the original MX record for “yale.edu” to point to “connect-yale-edu.mail.protection.outlook.com” and we take the teas and dump them in Boston harbor (we can have a party to celebrate the success of the project, but dressing up as native Americans is no longer appropriate because it is “cultural appropriation”).

Exchange Online will receive the original address in the mail without any translation through the Alias table. This means that Exchange has to understand “howard.gilbert@yale.edu”, while if the Mail Relays had preprocessed this alias they would have forwarded it as “gilbert@connect.yale.edu”.

In practice, this means that every Alias name has to be mapped to a Recipient (as explained above). In the past, some Aliases were not recognized by Exchange, so it would forward that message to the Mail Relays who in turn would translate the alias to a MAILBOX value and send it back. To get rid of the Mail Relays, Exchange has to recognize every alias immediately.

Done: Populate the ProxyAddresses list of student Eliapps users with any Secondary Aliases that have a MAILBOX that points to their Eliapps account.

Done: There may be Eliapps accounts that are the Primary Email Alias of people who are not current students and were not configured as part of the student class distribution list fix. Their Primary and Secondary aliases should be configured in their User objects if possible, or in a Contact if they also have an O365 account occupying the User object.

Done: All remaining Email Aliases (excluding aliases pointing to some sort of Exchange account or a Primary Eliapps account) get turned into Contacts. We do not create or look for User objects for them. A new Contact is created in some new OU, and the MAILBOX becomes its TargetAddress and all the ALIAS_NAMEs with that MAILBOX value become entries in its ProxyAddresses list.

ToDo: The Legacy ADDailyUpdater is deleting Secondary Email Aliases from the ProxyAddresses list. This must be fixed.

Decision Point: The personal O365 and Eliapps accounts are plausibly related to IAM, although we are not in the business of creating Secondary Aliases. It may be decided that it is useful to continue to audit the Alias Table and the ProxyAddresses list to see if somehow personal Alias changes slipped in without generating the required ProxyAddress changes. However, the creation and modification of shared mailboxes and departmental accounts is not an IAM function and because these objects have no information in Identity tables, we are not in a position to audit them properly. We should consider this a one time conversion of Alias information into AD objects and properties that configure Exchange Online. Going forward, all scripts, tools, and procedures used to generate departmental accounts and create their aliases should also manage their Contacts with the mail routing information.

Cleanup: If tools are created or converted to manage non-personal mail accounts, then we should consider establishing some proper rules and converting existing entries to match these rules. In particular, the practice of creating an Email Alias and a Dependent Netid and assigning ownership of the Alias to the person who owns the dependent Netid causes serious problems. People leave the university without transferring both the alias and the Dependent Netid to someone else. Then when their personal mail gets deprovisioned, the Secondary Alias for the group account remains attached to the inactive AD User object. The correct thing to do is the assign ownership of the Alias to the Dependent Netid that represents the shared mail account. The account can then stand alone, and if the owner fails to transfer the Dependent Netid to someone else, well the Dependent Netid is still active even if the former owner is inactive. This fix is not technically part of the Mail Relay project, but if we are fixing all the tools for this type of account we should fix this at the same time.

People with an Eliapps Primary Alias and a Personal O365 Secondary Alias

A Personal O365 Email Alias has a MAILBOX of “netid@connect.yale.edu”. By a “personal” account, I am not including Secondary Aliases owned by a person that point to Email accounts owned by a Dependent Netid (typically used for shared mailboxes for groups or departments).

IAM code that only has access to databases, like the ACS1 tables, has to regard the MAILBOX in the alias as authoritative. A more direct check, but one available only to Powershell, is to call the ExchangeOnlineManagement Get-Recipient command to determine if a User object is a “UserMailbox” type of recipient. This directly determines if Exchange Online has an O365 mail account associated with the object. Without this check, there can be Aliases for a mail account that doesn’t exist, and mail accounts that in violation of Yale Policy have no Alias associated with them. These are errors that should be found and fixed manually. These errors arise from mismanagement of accounts by admins and not by normal changes to Identity status. The IAM functions in IIQ cannot be expected to fix them.

However, this type of error does not result in misdelivered Email because in neither case should anyone have an expectation that mail will be delivered to either a non-existent account or to an account with no Alias. There is some small chance of errors when someone who left Yale years ago and currently has such errors in their configuration were to try to return to the university and get a new mail account.

However, a small number of people violate Yale Policy by having a Primary Email Alias that points to Eliapps while also having an O365 mail account. This creates an ambiguity. Currently the Mail Relays deliver incoming mail to Eliapps, while mail sent from Exchange Online to the same address goes to the O365 mailbox.

However, the real problem is that this will try to generate duplicate ProxyAddresses. The Primary Email Alias (no matter what MAILBOX value it has) sets the UPN and MailNickName, and Exchange Online will always insert the UPN into the list of ProxyAddresses even if it is not in the Local AD list. Meanwhile, a secondary Eliapps account belonging to someone who owns an O365 mail account will generate a Contact object, and the ProxyAddresses list in the Contact will include the Aliases pointing to that account, and the first (primary) email address in that list will be the Primary Alias address.

Exchange Online will refuse to add the ProxyAddress to the second object it processes, which will generally be the Contact. The following list of Primary Aliases seem to have this problem, but only 5 of them represent current users. If nothing is done, then they will cease to get mail in their Eliapps account through the Primary Alias. All of them need to be rechecked before the Mail Relays are retired.

People with Eliapps Primary Alias, No O365 Secondary Alias, but are “UserMailbox” Recipents (have a mailbox) in Exchange

Exchange reported on the day the list was created that the following users have an O365 mailbox (their Recipient Type was “UserMailbox”). However, no Alias points to this mailbox. The Alias instead points to their Eliapps account.

Lets take cav7. The Primary Alias is claudia.villano with a MAILBOX of claudia.villano@bulldogs.yale.edu. Current affiliation is Staff, but you only get Eliapps if you were a student, so this is a former student who became Staff and was given an O365 account manually but the alias was never changed. Delivery here is the same as for Morrow. The Relays follow the Alias and deliver external mail to Eliapps, while O365 discovers that SMTP:claudia.villano@yale.edu is a ProxyAddress of a UserMailbox Recipient and delvers mail with the same address to O365. When the Mail Relays go away, external mail will start being delivered to O365.

This list is a lot longer than the five people with aliases, and each account has to be examined manually if we are to provide exact notification. Alternately, we could just bulk mail all the @bulldogs.yale.edu mailbox addresses in the list and tell the user that after the Mail Relay retirement date, all their mail will start arriving in O365 and if they don’t want that they should contact the Help Desk to delete their O365 account.

AD Daily Updater Bug Entries

The Legacy ADDailyUpdater code adds two ProxyAddresses “netid@connect.yale.edu” and “first.last@connect.yale.edu” to the 17,000 student Primary Eliapps User objects. These entries are misleading when viewed, but they have no affect on any actual mail processing and do not have to be fixed.

Exchange Online first looks at the type of User before looking at the ProxyAddresses. It discovers these users are of type “MailUser” (meaning they have no O365 mailbox and so mail passes through Exchange and is forwarded to what Exchange calls the ExternalEmailAddress (called a TargetAddress in AD).

This only confuses administrators and any Powershell script that makes decisions based on the presence of a “connect.yale.edu” ProxyAddress in the AD. We have had this problem for over a month and no ITS staff have noticed and complained, so it doesn’t have to be fixed now.

This cannot be fixed while the Legacy ADDailyUpdater is running because it will just put the bad data back in. After it is fixed or retired, a one time Powershell script should delete all these unnecessary ProxyAddresses.