Open relay

Hello,
I need to allow an external(cloud) app to send e-mail via on-premisse exchange server.
So,I need to configure open relay for two public IP addresses.
I checked those two IP address and they are Microsoft IP addresses.So,I presume it is Azure app.
Is it OK to allow open relay to public IPs like Microsoft?
If it is OK,I only need to add those two IPs on receive connector(anonymous) ?
LVL 1
AndyAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

ste5anSenior DeveloperCommented:
1) Yes. But is it sufficient? Not necessarily. Cause Cloud means also shared. Thus an evil attacker on the same Microsoft IP may than misuse your open relay.

Maybe you should look into Azure to on-premise VPN like Connect an on-premises network to Azure using a VPN gateway.
0
MichelangeloConsultantCommented:
Ciao,

Ms-Exch-SMTP-Accept-Any-Recipient – allows to relay email outside of your organization, as described in the article above.

Moreover, you may need to add:
Ms-Exch-SMTP-Accept-Any-Sender – You may want to bypass checks imposed on the sender address i.e. you may want to allow external senders. It may not be advised to set it but I list it for the dogmatic Sake Of Completeness

Ms-Exch-Bypass-Anti-Spam– Allows to bypass checks that may prevent delivery of emails when sent from malformed sender domains (useful for appliance reports and whatsnot)
0
Michael B. SmithExchange & Active Directory ExpertCommented:
If you are already in Microsoft's cloud and need to send email, I recommend you take a look at Azure SendGrid. It's "free" for up to 25K emails a month.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Creating Active Directory Users from a Text File

If your organization has a need to mass-create AD user accounts, watch this video to see how its done without the need for scripting or other unnecessary complexities.

AndyAuthor Commented:


ste5anSenior Developer

Comment posted36m
1) Yes. But is it sufficient? Not necessarily. Cause Cloud means also shared. Thus an evil attacker on the same Microsoft IP may than misuse your open relay.

That what i am afraid of.

If you are already in Microsoft's cloud and need to send email, I recommend you take a look at Azure SendGrid. It's "free" for up to 25K emails a month.

Company is  not in the cloud but this app is in the cloud.So Azure SendGrid wont work?But company has test mailboxes on office 365(@onmicrosoftdomain)
0
Michael B. SmithExchange & Active Directory ExpertCommented:
If they have test mailboxes in Office365 then they have access to the Azure portal and can set up SendGrid.
0
AndyAuthor Commented:
Michael,
Thank you for hint about sendgrid.
I will check this option.Never heard about sendgrid.
I will try to google it
So,company is on-premisse and has office 365 just for test and app is from another company in cloud.
If someone have advice how to configure send grid in this situation :-)
Thank you
0
Shaun VermaakTechnical Specialist/DeveloperCommented:
I need to allow an external(cloud) app
Do you have control over it? Can you not use EWS?
0
Michael B. SmithExchange & Active Directory ExpertCommented:
portal.azure.com and login using the global admin for the account

go to "all services"

enter "sendgrid" in the search box

click on the "sendgrid" result

on the following slab, click on "create sendgrid account"

follow the bouncing balls. :-)
0
AndyAuthor Commented:

Shaun VermaakTechnical Specialist/Developer

 
Do you have control over it?

I dont have control on this cloud app.
0
AndyAuthor Commented:
Michael,
thank you
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Exchange

From novice to tech pro — start learning today.