Exchange CAS-Servers Hostname Send Connector


currently we have the following problem.
We have two Backendservers and two cas-servers working as "Proxy through client access server".

Now we have one FQDN configured on Send Connector ""
"" has an A Record to IP-Address

But CAS-Servers have IP-Addresses and

Now if an email is send it is shown in email header like this

"Received from with IP-address"
"Received from with IP-address"

But spamfilters maybe filter this as spam, because points to ip-address

How to resolve this?
I can not configure any ip-addresses on send connector.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

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.

Will SzymkowskiSenior Solution ArchitectCommented:
This does not matter. As long as you you sending from the same external public IP address an internal IP does not matter. The minimum requirement to send email on the internet without being flagged as spam follows...

- A record for
- MX record for
- Reverse record (PTR) IP > (you need to contact your ISP to get them to create the reverse record for you)

As long as you have the above you will not be flagged as a spammer.

Another addtional step you can do is create an SPF record. This is another level of authenticity. With an SPF record you have more flexibility in that you can add multiple external IP addresses as Sending Servers on the internet.

So that being said spam filters do not care about the internal IP address of where the email came from as it could have come from several different internal Exchange servers. The External IP address is what is important here.

uhscaleAuthor Commented:

no both cas servers have an external ip-address and are connected directly to the internet. And that's the problem.

So cas server 1 is sending with ip-address and hostname ""
Second cas server is sending with ip-address and hostname ""

I found no way to configure one ip-address to both cas servers. Or configured individuell fqdn for every cas server.

In Exchange 2010 this was working without any problems.
Will SzymkowskiSenior Solution ArchitectCommented:
Ok no problem. As i stated already all you need to be able to do is create a SPF record and add both IP's to this record. This will allow you to send from these different IP for the same

Thats all that is required.


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
uhscaleAuthor Commented:

ok thanks
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

From novice to tech pro — start learning today.