Exchange 2013 SP1 with 1 DAG and 2 member servers. We have a block of 5 ip's, 1 is designated for exchange only. Sent email is being sent from the ip that is not designated to exchange services, specifically SMTP. Is there a way to configure exchange to use the ip that is designated for smtp exchange? Our DNS record with our ISP is correct and all the other public DNS records. So when outgoing email uses the non-designated ip, users get the message is delayed email. And that email says the ip is on spamhaus list. The ip designated for exchange is NOT on any blocklists. Our firewall is configured in such a way to use the ip designated for exchange services. This use to work and it stopped working when we had a power outage that lated longer than the UPS's. Any ideas?

in your Send connector just use the One IP instead of all assigned ip address in your send connector

I don't follow your suggestion. In the scoping selection in Our send connector:

Notice the address space is for routing email to and the "*" means anything on the internet. If I change this to the ip or FQDN, no one can send email. The bottom selection you cannot enter anything only select a server. Is this where you are referring to?

The delivery selection of the send connector is for sending email using a smart host or mx. We are using mx.

• Edited by forgiven 8 hours 43 minutes ago

Hi

You have to run Set-SendConnector SourceIPAddress x.x.x.x from the EMS in order to set the source ip address (IP address of your Exchange server) for outbound email.


Then you need to accomplish this with a router/firewall with a feature called Policy Based Routing.
Create a firewall/NAT rule to NAT outbound traffic from that ip address to your preferred public ip address.
With this you could make a rule like: When traffic is coming from my mail server AND the destination port is 25, send the traffic through this ISP from one of your public IP.

Agree with Sathish
You will have to do many to one NAT in your firewall as below.
Server1: 192.168.0.1  --> 91.140.235.88           port  25
Server2: 192.168.0.2  --> 91.140.235.88           port  25

If your servers configured as above your source will be 91.140.235.88 from both the servers. 
I hope you have PTR created for your external IP. If not please inform your ISP to create PTR for your external IP

well I gave the hint here - i don't have exchange in front me me to give you step by step but this is what Satish made step by step instructions for you.