Group Email by Domain Users

[dcmoody]

I recently switched from GSuite/Google Workplace.  Google was fairly easy to administer and I'm finding Microsoft a little more difficult.

In Google, I could easily create a distribution group and allow anyone in my organization (domain user) to email the group, but only the members could read/receive the emails.  I use this for department emails.

How can I go about this in M365?  I do not want to enable external senders completely, as I do not want anyone outside my organization emailing that group.

On another note, if there is a guide somewhere that shows Google vs Microsoft ways of doing things, I'd love to see it.

Appreciate the help!

-David

[#2]

What you are asking for is the default behavior in O365, for both "traditional" distribution groups and "modern" Office 365 groups. There's no need to configure anything.

[#3]

@VasilMichev I continue to get NDRs when sending a message to one of these groups.  It is just a Unified or new distribution group.

Here is the distribution list config in case I have inadvertently configured it incorrectly.

I appreciate the help

RunspaceId                             : 2a2eaf8e-7422-4792-bd80-a6bb8a520a3d
AccessType                             : Private
AuditLogAgeLimit                       : 90.00:00:00
AutoSubscribeNewMembers                : True
AlwaysSubscribeMembersToCalendarEvents : True
CalendarMemberReadOnly                 :
CalendarUrl                            : https://outlook.office365.com/owa/?pat
                                         h=/group/*******/calendar
Database                               : NAMPR19DG029-db093
ExchangeGuid                           : 78c028d9-4bb9-4760-bcc2-99de1e5902a0
FileNotificationsSettings              :
GroupSKU                               : Default
InboxUrl                               : https://outlook.office365.com/owa/?pat
                                         h=/group/********/mail
IsExternalResourcesPublished           : True
IsMailboxConfigured                    : True
Language                               : en-US
MailboxProvisioningConstraint          :
ManagedByDetails                       : {*****}
Notes                                  :
PeopleUrl                              : https://outlook.office365.com/owa/?pat
                                         h=/group/******/people
PhotoUrl                               : https://outlook.office365.com/EWS/Exch
                                         ange.asmx/s/GetUserPhoto?email=*******
ServerName                             : mn2pr19mb3007
SharePointSiteUrl                      :
SharePointDocumentsUrl                 :
SharePointNotebookUrl                  :
SubscriptionEnabled                    : True
WelcomeMessageEnabled                  : True
ConnectorsEnabled                      : True
IsMembershipDynamic                    : False
Classification                         :
GroupPersonification                   :
YammerEmailAddress                     :
GroupMemberCount                       : 17
MailboxRegion                          :
GroupExternalMemberCount               : 0
AllowAddGuests                         : True
WhenSoftDeleted                        :
HiddenFromExchangeClientsEnabled       : False
ExpirationTime                         :
DataEncryptionPolicy                   :
ResourceProvisioningOptions            : {}
ResourceBehaviorOptions                : {}
ServiceEndpointUris                    : {}
SensitivityLabel                       :
InPlaceHolds                           : {}
EmailAddresses                         : {smtp:*******
                                         , SMTP:*******}
PrimarySmtpAddress                     : ********
Name                                   : all_4c001ab1-f883-41b9-8fc9-26765a852f
                                         b9
DisplayName                            : All Staff
RequireSenderAuthenticationEnabled     : True
ModerationEnabled                      : False
SendModerationNotifications            : Always
SendOofMessageToOriginatorEnabled      : False
BypassModerationFromSendersOrMembers   : {}
ModeratedBy                            : {}
GroupType                              : Universal
IsDirSynced                            : False
ManagedBy                              : {****}
MigrationToUnifiedGroupInProgress      : False
HiddenGroupMembershipEnabled           : False
ExpansionServer                        :
ReportToManagerEnabled                 : False
ReportToOriginatorEnabled              : True
Description                            : {}
BccBlocked                             : False
AcceptMessagesOnlyFrom                 : {}
AcceptMessagesOnlyFromDLMembers        : {}
AcceptMessagesOnlyFromSendersOrMembers : {}
AddressListMembership                  : {\Default Global Address List,
                                         \GroupMailboxes(VLV), \All
                                         Recipients(VLV), \Groups(VLV)…}
AdministrativeUnits                    : {}
Alias                                  : all
OrganizationalUnit                     : nampr02a003.prod.outlook.com/Microsoft
                                          Exchange Hosted Organizations/******
CustomAttribute1                       :
CustomAttribute10                      :
CustomAttribute11                      :
CustomAttribute12                      :
CustomAttribute13                      :
CustomAttribute14                      :
CustomAttribute15                      :
CustomAttribute2                       :
CustomAttribute3                       :
CustomAttribute4                       :
CustomAttribute5                       :
CustomAttribute6                       :
CustomAttribute7                       :
CustomAttribute8                       :
CustomAttribute9                       :
ExtensionCustomAttribute1              : {}
ExtensionCustomAttribute2              : {}
ExtensionCustomAttribute3              : {}
ExtensionCustomAttribute4              : {}
ExtensionCustomAttribute5              : {}
GrantSendOnBehalfTo                    : {}
ExternalDirectoryObjectId              : 4c001ab1-f883-41b9-8fc9-26765a852fb9
HiddenFromAddressListsEnabled          : False
LastExchangeChangedTime                :
LegacyExchangeDN                       : /o=ExchangeLabs/ou=Exchange
                                         Administrative Group (FYDIBOHF23SPDLT)
                                         /cn=Recipients/cn=0c641af02a094c2eb7b1
                                         a3ce470a8036-all_491d5d3
MaxSendSize                            : 35 MB (36,700,160 bytes)
MaxReceiveSize                         : 36 MB (37,748,736 bytes)
PoliciesIncluded                       : {}
PoliciesExcluded                       : {{26491cfc-9e50-4857-861b-0cb8df22b5d7
                                         }}
EmailAddressPolicyEnabled              : False
RecipientType                          : MailUniversalDistributionGroup
RecipientTypeDetails                   : GroupMailbox
RejectMessagesFrom                     : {}
RejectMessagesFromDLMembers            : {}
RejectMessagesFromSendersOrMembers     : {}
MailTip                                :
MailTipTranslations                    : {}
Identity                               : all_4c001ab1-f883-41b9-8fc9-26765a852f
                                         b9
Id                                     : all_4c001ab1-f883-41b9-8fc9-26765a852f
                                         b9
IsValid                                : True
ExchangeVersion                        : 0.10 (14.0.100.0)
DistinguishedName                      : CN=all_4c001ab1-f883-41b9-8fc9-26765a8
                                         52fb9,OU=*****,
                                         OU=Microsoft Exchange Hosted Organizat
                                         ions,DC=NAMPR02A003,DC=prod,DC=outlook
                                         ,DC=com
ObjectCategory                         : NAMPR02A003.prod.outlook.com/Configura
                                         tion/Schema/Group
ObjectClass                            : {top, group}
WhenChanged                            : 12/11/2020 11:32:43 AM
WhenCreated                            : 12/3/2020 11:58:37 AM
WhenChangedUTC                         : 12/11/2020 4:32:43 PM
WhenCreatedUTC                         : 12/3/2020 4:58:37 PM
ExchangeObjectId                       : ebc6953a-f46a-4aed-ab54-ea71ca494863
OrganizationId                         : NAMPR02A003.prod.outlook.com/Microsoft
                                          Exchange Hosted Organizations/***** - NAMPR02A003.pr
                                         od.outlook.com/ConfigurationUnits/*****/Configuration
Guid                                   : ebc6953a-f46a-4aed-ab54-ea71ca494863
OriginatingServer                      : SN6PR02A03DC004.NAMPR02A003.prod.outlo
                                         ok.com
ObjectState                            : Changed

[#4]

I should also note that the messages being rejected are being sent by an automated system sending via Sendgrid.

[#5]

Based on your original question, I thought you *didnt* want external messages to the group? If you do want to enable this, toggle the RequireSenderAuthenticationEnabled flag. If you want to only allow messages from specific external addresses, best create a Mail flow rule.

[#6]

@VasilMichev Appreciate the help.  Some of your questioning led me to look into some items further.

What I have is several "external" systems that I want to be able to email distribution lists/groups.  Those systems do not authenticate but rather send via SendGrid.

For now I think I have it accomplishing what I wanted by allowing "external" senders, but then creating a dynamic distribution list with all users/groups and then it has allowed the message to be sent.

I'm not sure if this is the best way to accomplish this or not, but for now, it seems to be working.

[#7 · Accepted solution]

Either Dynamic DG or O365 Group would do, the problem is that *everyone* can send messages to it once you toggle the flag. To restrict this, the best option would be to use Mail flow rules, as they give you a lot of freedom in terms of conditions you can use to "match" the sender.