Microsoft Exchange 2016 Send Connector Scoping

[Inertia]

Its possible in Microsoft exchange to have multiple send connectors and use the scoping so that mail sent to a specific domain are sent through a specific relay, whilst emails sent to other domains are sent directly to their server via DNS.

 

I manage a multi tenanted Exchange 2016 server with multiple groups of users with different domains.

 

Is it possible to somehow setup send connectors that are scoped based on where the mail is coming from rather than where it is going to ? For example users on domain 123.com will be relayed through smtp.123-isp.com with authentication, whilst mai lsent from users on domains 456.com are relayed through a different server smtp.456.com with authentication, whilst users sending from domain 789.com send directly to the recipients server by DNS.

 

any pointers would be appreciated.

 

Thanks

[sc302 Veteran]

no.  not really. 

 

look at how the big boys do it.  even if they host your domain on their servers, mail is still coming from outlook or google mail servers. 

[Inertia]

Having problems with some mail servers rejecting some of the domains, I have reverse DNS setup, the domains have correct SPF records, its in a DC not on a DSL line or something.

 

I bet there is a Linux way around it, setup a Linux VM and relay all mail from the exchange server to that first, then have the Linux box dish out the mail directly or via relays depending on the sender domain.

 

Perhaps i should've posted this in those forums, I was being too hopeful that exchange would have an internal mechanism for this!

[xbamaris]

We use Amazon SES as a Smart Host setup. Super cheap. How much mail do you send? (Not receive)

 

[Inertia]

From the entire server, 1,000-2,500 messages per day on weekdays, more like 500 per day at weekend. so ~10-13k a week, not sure how much data volume.

 

Just having a read up on Amazon SES now, what is their smart-host reputation like ? I'm guessing you don't have problems with mails getting delayed then failing, or just rejected by other hosts ?

[sc302 Veteran]

No. I have a direct line from comcast. Had them put a ptr record in and non rejected or delayed. 

 

Isp has to put in the ptr record.  Or your D.C. Isp has to. 

[xbamaris]

I've yet to have major issues. Sending to all major emails without any rejects. Set it up with all the correct DKIM information and other things and it should work perfectly and securely.

 

You'd have to change your SPF to point to Amazon SES servers

 

EDIT: If you haven't used Amazon Web Services you can do the Free Tier for 2000 messages per day free (not sure if it includes data outgoing) But even 2500 messages a day with 5 GB of transfer, probably $5-$10 monthly and it would vary. You can use this: http://s3.amazonaws.com/calculator/index.html to estimate Though it includes Free Tier pricing by default but I'm not sure how to turn that off, but still, estimated $5-$10 seems fair

Edited December 8, 2016 by xbamaris

[Inertia]

Thanks, I have used AWS before, plus I think the free teir only works for messages coming from their services (EC2 instances etc) not servers external to them.

 

However $5-10 monthly seems a small price to pay! Thanks for the tip!

[+BudMan MVC]

1 hour ago, Inertia said:

Having problems with some mail servers rejecting some of the domains, I have reverse DNS setup, the domains have correct SPF records

And why are they rejecting it.. Are you getting a kickback that gives you an error code?

 

Could you post some of the domains in question or PM them to me so I can take a look at how it looks from the internet.. Could you send me email from these domains.. I can give you my personal email account to use in a pm.

[Inertia]

On 08/12/2016 at 7:21 PM, xbamaris said:

I've yet to have major issues. Sending to all major emails without any rejects. Set it up with all the correct DKIM information and other things and it should work perfectly and securely.

 

You'd have to change your SPF to point to Amazon SES servers

 

EDIT: If you haven't used Amazon Web Services you can do the Free Tier for 2000 messages per day free (not sure if it includes data outgoing) But even 2500 messages a day with 5 GB of transfer, probably $5-$10 monthly and it would vary. You can use this: http://s3.amazonaws.com/calculator/index.html to estimate Though it includes Free Tier pricing by default but I'm not sure how to turn that off, but still, estimated $5-$10 seems fair

I have moved my biggest problem server to relay via SES and changed the SPF's setup DKIM etc, and it works really really well, i'm impressed and its only costing me less than $1 a month so far in usage. Even if I point all of my servers and all of my email traffic here I cant see it costing more than ~ $10 a month

 

However the attachment limit seems to be 10MB, is there any way I can increase this with amazon ? My clients are used to being able to send 20-25mb attachments?  or is it possible to use a rule in exchange to send via AWS for email 10mb and below in size and send direct for emails bigger than this?

 

 

On 08/12/2016 at 8:10 PM, BudMan said:

And why are they rejecting it.. Are you getting a kickback that gives you an error code?

 

Could you post some of the domains in question or PM them to me so I can take a look at how it looks from the internet.. Could you send me email from these domains.. I can give you my personal email account to use in a pm.

Sorry for ignoring you Bud man and thank you for offering your help, I just haven't had chance to take you up on it yet! Plus the SES solution seems great for now.