In MS Exchange 2013 With out this service also Inbound/Outbound is working, Can any one answer below queries?

what this service is for?

Impact on what area if it is disabled?

Hi Gentela,

Thank you for your question.

Are there any errors when you send emails? I suggest we could send those errors to ibsexc@microsoft.com for our troubleshooting.

Could you tell me which service has been disabled? Why you want to disable it?

When Exchange installation was completed, we could send/receive email in Intranet, if we want to send/receive emails from Internet, we should register MX record in our ISP. Then we should create send/receive connector on CAS server in Exchange2013.

There are many services which affects inbound\outbound, for example: Microsoft Exchange Frontend Transport service, Microsoft Exchange Mailbox Transport Delivery, Microsoft Exchange Transport Submission, Microsoft Exchange Transport and so on.

We could refer to the following link:

https://technet.microsoft.com/en-us/library/aa996349(v=exchg.150).aspx

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim