Russell
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Sending as 3rd-party domain address with Office 365
I'm in the process of moving a customer from an on-site Exchange to Office 365, but I've hit a roadblock. One of the mailboxes needs to send from an external address, instead of an address on the domain they own. This works fine with their on-site Exchange, as I can just change their default SMTP address. A POP3 connector fetches mail from the external address, and any mail they send leaves their Exchange server as that address. They essentially have Exchange functionality for their external POP3 address.
Office 365 Exchange won't let me add the external address, as it's not an accepted domain. I can't add it as an accepted domain because I can't verify the domain (the domain is owned by the franchisor, not my customer the franchisee). I've added the external address, via OWA, as a Connected Account. I've changed the Default Reply Address to the external account. I've given it a few days to synchronise, but it still wants to send from their own domain via Outlook and OWA. The best I can do is to manually select the From address in OWA, and that works (except it sends it "On behalf of").
Has anybody come across this hurdle before and been able to solve it?
Some people have claimed that the Connected Account and Default Reply Address in OWA has worked for them, even when sending from Outlook, but it's not the case in my testing. I'd be happy with a result that sends directly from the O365 servers (there's no SPF record on the franchisor's domain), or even if there's a way to send via the franchisor's SMTP server. I'd really like to avoid the "on behalf of" scenario, but it's better than nothing.
Office 365 Exchange won't let me add the external address, as it's not an accepted domain. I can't add it as an accepted domain because I can't verify the domain (the domain is owned by the franchisor, not my customer the franchisee). I've added the external address, via OWA, as a Connected Account. I've changed the Default Reply Address to the external account. I've given it a few days to synchronise, but it still wants to send from their own domain via Outlook and OWA. The best I can do is to manually select the From address in OWA, and that works (except it sends it "On behalf of").
Has anybody come across this hurdle before and been able to solve it?
Some people have claimed that the Connected Account and Default Reply Address in OWA has worked for them, even when sending from Outlook, but it's not the case in my testing. I'd be happy with a result that sends directly from the O365 servers (there's no SPF record on the franchisor's domain), or even if there's a way to send via the franchisor's SMTP server. I'd really like to avoid the "on behalf of" scenario, but it's better than nothing.
ASKER
Unfortunately, this hasn't changed anything. I can still manually "Send as" from OWA (as before, with just the Connected Account configured), and it still says "on behalf" when received. I'm still unable to set the external domain as the default email address.
According to the Microsoft Support comment in that thread, it's not possible, at least as of a year ago. It's disappointing that there's no facility to spoof the sender (as with on-site Exchange), or send via an external SMTP server, as with GMail.
I'm hoping someone might have a trick up their sleeve, to save having to configure a Postfix relay server which could do the job that O365 can't.
The only other thing I can think of is to see if the franchisor would be willing to add a TXT record, allowing me to add their domain to the account. I'm not sure if O365 would only let one account do that and/or if it would confuse routing for the domain.
According to the Microsoft Support comment in that thread, it's not possible, at least as of a year ago. It's disappointing that there's no facility to spoof the sender (as with on-site Exchange), or send via an external SMTP server, as with GMail.
I'm hoping someone might have a trick up their sleeve, to save having to configure a Postfix relay server which could do the job that O365 can't.
The only other thing I can think of is to see if the franchisor would be willing to add a TXT record, allowing me to add their domain to the account. I'm not sure if O365 would only let one account do that and/or if it would confuse routing for the domain.
Office 365 will only let one account to do that, so if you have added them into your tenant, then this will prevent them from registering in Office 365. (unless you remove from them your list again).
I am trying to manually do it at my end to work out is there any other mechanism to do so.
and there are really no option to spoof sender address with authenticated user.
https://technet.microsoft.com/en-us/library/dn554323(v=exchg.150).aspx
I am trying to manually do it at my end to work out is there any other mechanism to do so.
and there are really no option to spoof sender address with authenticated user.
https://technet.microsoft.com/en-us/library/dn554323(v=exchg.150).aspx
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ASKER
The solution works, but it's not ideal. Until Microsoft change the behaviour of O365, using a 3rd-party mail server is the only way. Ideally, you should restrict the SMTP port on the 3rd-party server to only accept connections from O365 servers. There is an XML list of current IP addresses O365 use, but it would require scripting a daily cron job to check and update the firewall rules. I'll add it to my To Do list :)
https://community.office365.com/en-us/f/158/p/260375/797288#797288