**Hi Adobe Community,**
I'm working on an Adobe Campaign Classic v7 setup on RHEL 9 and need some guidance on MTA configuration for production deployment.
**Current Setup:**
- Adobe Campaign Classic v7 on RHEL 9 server
- Using Postfix as external mail relay (port 25) - currently working well
- Successfully sending emails through workflows via Postfix relay
**My Questions:**
1. **Built-in MTA Capabilities**: Can Adobe Campaign Classic v7's built-in MTA handle both sending and receiving emails without requiring external relays like Postfix?
2. **Configuration Resources**: Where can I find official Adobe documentation for configuring the built-in MTA?
3. **Volume Capacity**: What are the daily email volume limits and performance characteristics of the built-in MTA?
4. **Production Recommendation**: For production environments with high-volume email campaigns, what do you recommend? Built-in MTA or external MTAs like Postfix/Sendmail?
5. **RHEL 9 Compatibility**: Any specific considerations when running on RHEL 9?
**What I'm trying to achieve:**
Simplify the architecture by potentially removing external mail server dependencies while ensuring production-grade reliability and performance.
**Looking for:**
- Real-world production experiences
- Performance comparisons
- Official Adobe recommendations
- Configuration best practices
Has anyone successfully deployed Campaign Classic v7 using only the built-in MTA in production? What challenges or benefits did you encounter?
Thanks in advance for sharing your expertise!
**Environment Details:**
- Adobe Campaign Classic v7
- RHEL 9
- Current external MTA: Postfix (working)
