How to create mailbox for system email in exchange 2016?

To send email.. you can use any dummy email address.. mailbox or contact or transport rule is not required..

How and where you configured the system alerts

as Mr. Rajkumar said its no need of mailbox..  but if you create a mailbox u'll have a track of emails and reporting to your mailbox. could be advisable.

from where you are sending this email?

Non-Authenticated relay:
If this is your monitoring server, u need separate receive connector with "Exchange Servers" as authentication and anonymous users as permissions group
Then replace allowed IPs with the IP of server being need to send emails
Follow 3rd scenario in below link
https://docs.microsoft.com/en-us/exchange/mail-flow/connectors/custom-receive-connectors?view=exchserver-2019

Authenticated Relay:
If the system from where you sending emails is accepting authentication for user, then above relay is not required and you can directly configure credentials on server itself and sent emails from that server will remain authenticated

Note that you can keep any email address as "from address" but its advisable to keep email address domain from accepted domain only
This will pass SPF validations even if you want to relay emails on internet later point of time

Hi everyone,

My system will send out email using system@company.com and this system@company.com email will be redirect to few admin, so do we need mailbox for system@company.com?

No. Not required..

Redirection settings using Transport Rule to your admin also dont required mailbox

Hi Raj, please correct me if i'm wrong.

Is the only way to archive my scenario, is to create Mail contact in EMC and create transport rule to redirect the email if detected recipient is system@company.com?

If there's a better alternative way, please do advise.

Another question is about alias email (no mailbox just virtual email address), how can i create alias email that is tie to a primary mailbox?

Thanks.

its not important to whom you are sending email as long as recipient address in internal

Important is from where you are sending emails

The server / system from where you are sending emails must be allowed to send / relay emails through exchange server if sender address you are using is not authenticated, in other words don't have username / password to authenticate with exchange or system has no way to input authentication data for that sending email ID (user ID), In that case you need custom receive connector to receive emails from sender system / server as mentioned earlier
Else make sure that it can send emails post proper authenticating by exchange server

Hi Mahesh,

Thanks for the info. means that if i want my exchange able to receive email from other system/application server i must enable custom receive connector ?

But all my default frontend receive connector are opened to receive all IP address and from anonymous users as well, do i still need to create this custom connector?

Thanks .

Default frontend receive connector is there to receive emails from internet which is typically known as anonymous connections reached via DNS MX lookup and that is also only to your authoritative SMTP domain

You are trying to send email from internal server / system directly to exchange server internal IP which is considered as unauthenticated relay unless you use some AD username \ password as SMTP authentication and hence exchange rejects those messages. refer my earlier comments
That is why majority of applications provide you interface where you need to provide username and password for SMTP authentication to avoid unauthenticated delivery

If you don't have such interface, then you explicitly need to tell exchange server that accept emails from specific server IPs or hostnames through custom connectors without any authentication (whitelisting)
This will allow only that specific servers to relay emails internally and same time saves exchange from acting as open relay

https://docs.microsoft.com/en-us/exchange/mail-flow/connectors/custom-receive-connectors?view=exchserver-2019

Hi Mahesh,

Thanks for your feedback.

I have created a custom receive connector and speficic the application server IPs with port 25.

I requested my application teams to trigger an email from the system to send it to my exchange server, unfortunately i'm not able to receive the email.

Is there any configuration i need to configure?

have you granted exchange servers permission to connector and granted "Anonymous users" permissions?

Also this connector will not be able to send email to external addresses?

Hi Mahesh,

After going through the configuration file in internal application server, they are using authentication that have "support@company.com" and password "XXX"

thats mean i need to configure smtp authentication? how can i configure that?