SMTP Gateway and Email Security Expert Required

@iosifpeterfi

Hello, I'm Iosif, a systems and email security engineer with experience in Postfix/SMTP gateway design, SPF/DKIM/DMARC alignment, AWS infrastructure, and Exchange Online connector configuration. The challenge here goes beyond a basic relay. Building a multi-tenant gateway that isolates tenant configs, maintains per-tenant IP reputation, and integrates synchronous DLP inspection without added latency requires careful architecture. My approach would start with tenant isolation and gateway core: - Postfix on EC2 with per-tenant transport maps and SASL authentication - Tenant identification via recipient domain lookup against DynamoDB or PostgreSQL - Dedicated IP pools per tenant with warm-up and reputation monitoring Security and compliance hardening would include: - SPF, DKIM signing (OpenDKIM), DMARC records configured per tenant domain - TLS client certificates for Exchange Online partner connectors with mutual TLS - Milter-based hook for synchronous DLP inspection before final relay Deliverables: - Production-ready multi-tenant SMTP gateway on AWS - Per-tenant SPF/DKIM/DMARC configuration and validation - TLS partner connector setup for Exchange Online - DLP relay integration point - Architecture diagrams and deployment runbook I have deployed Postfix mail infrastructure at MPDL and enterprise environments including multi-IP routing and deliverability tuning. Best regards, Iosif Peterfi

@ambientinfotech

Hello, I hope you are doing well. With 8 years of experience as a Server Administrator, I have extensive knowledge of various server technologies, troubleshooting techniques, and performance optimization. I can analyze and resolve any server-related issues efficiently based on your requirements. Please feel free to reach out if you have any queries or need assistance with server management. I’d be happy to help. Best regards,

@android2014213

Through my 10+ years in Linux/Windows System Administration, Devops, and Cloud Engineering, I have gained an unbeatable range of skills that make me a perfect fit for your SMTP Gateway and Email Security project. I have handled email gateway projects quite similar to yours, such as configuring secure SMTP Gateways on AWS and implementing multi-tenant architectures for high scalability and security. My significant experience with advanced DNS settings like SPF/DKIM/DMARC, as well as managing IP reputation for proper email delivery standards, ensures your project will be completed to the highest level of compliance. Additionally, I have a deep understanding of enterprise-level email routing and protocol deployment. I believe this knowledge is crucial for a role that requires integrating advanced solutions with Microsoft 365 Exchange Online. I know how to configure and test SPF, DKIM, DMARC records to ensure full compliance. I also bring in expertise in TLS client certificates deployment, Exchange Online TLS partner connectors configuration, which will contribute positively to transmitting secure emails post-synchronous security inspection as per your requirements.

@kumarashish99

Hello, I have experience designing secure, scalable email infrastructure on AWS and integrating enterprise SMTP gateways with Microsoft 365 Exchange Online. I can build a multi-tenant SMTP relay using Postfix/Haraka with AWS, implementing SPF, DKIM, DMARC, IP reputation management, TLS client certificates, Exchange Online Partner Connectors, and secure email routing after DLP inspection. My approach includes tenant identification through validated domains and connector mappings, centralized configuration storage with encrypted secrets, automated DNS validation, horizontal scaling behind load balancers, dedicated IP management, comprehensive monitoring, and high availability. I'll provide architecture diagrams, deployment automation, and detailed documentation to ensure a secure, maintainable, and production-ready email gateway with excellent deliverability and compliance. Thanks

@Solutionzhere

As an experienced technology expert with a strong background in Amazon Web Services (AWS) and Linux administration, I bring the necessary skills to design and deploy your secure, multi-tenant SMTP Gateway on AWS. My proficiency with Microsoft 365's offering aligns seamlessly with your project needs for integration with Exchange Online using Exchange Online Connectors. My career has equipped me with a deep understanding of email security best practices and an ability to identify vulnerabilities and implement the necessary measures to mitigate them. My experience designing scalable and highly available systems will ensure your solution is future-proofed for any expansion you might need. Though I don't have direct experience with Postfix, I am confident that my expertise in similar SMTP Gateway technologies will facilitate a smooth transition. Additionally, my familiarity with DNS settings (SPF, DKIM, DMARC, PTR) will prove valuable as we configure these for your solution. It would be a pleasure to provide comprehensive deployment documentation and easily understandable architecture diagrams – also within my skill set – so that you have all the tools needed to make the most of this system going forward.

@mohjib092

Hi, I can design and deploy a secure multi-tenant SMTP Gateway integrated with Microsoft 365 Exchange Online, including SPF, DKIM, DMARC, TLS partner connectors, IP reputation controls, DLP relay flow, and full architecture/deployment documentation. For tenant identification, I would use verified sending domains, connector rules, and isolated configuration storage per tenant to keep routing secure and scalable. Best regards, Muhammad Jibran Ahmed

@Web1devloper

Hello, I have strong experience with AWS, Linux (POSIX), Microsoft 365, Exchange Online, DNS management, and secure cloud infrastructure. I can design and implement a scalable, multi-tenant SMTP Gateway that integrates seamlessly with Exchange Online while following industry best practices for email security and deliverability. My approach includes building the gateway on AWS using a highly available architecture, implementing secure SMTP relay after DLP inspection, configuring SPF, DKIM, and DMARC for each tenant, managing IP reputation and warm-up strategies, deploying TLS client certificates, and configuring Exchange Online TLS Partner Connectors. Tenant identification and configuration will be handled through a secure centralized configuration store with proper isolation, enabling easy onboarding and future scalability. The solution will include monitoring, logging, failover planning, and detailed documentation with architecture diagrams and deployment guides. I've worked on cloud infrastructure, email routing, DNS configuration, SSL/TLS, AWS networking, and enterprise deployments, and I'm confident I can deliver a secure, maintainable, and production-ready solution. I would be happy to discuss your requirements in detail and propose the best architecture for your environment. Looking forward to working with you.

@jinufeb14

Having worked with enterprise clients on AWS with a specialty in Linux administration, I'm confident in my ability to design and deploy a secure, scalable, multi-tenant SMTP Gateway that's AWS-hosted and integrates smoothly with M365 Exchange Online. Alongside being conversant in multiple SMTP protocols and email routing, I possess substantial experience, and have implemented successful solutions related to email security. My capabilities extend to configuring DNS records (SPF, DKIM, DMARC, PTR), adopting best practices for queue management/monitoring and delivering comprehensive documentation - all of which are necessary for this project. Also, drawing from my familiarity with Google Workplace as a additional benefit I could provide support for its integration into the solution. In addition to meeting the requirements set out in the project description, my goal is always to create future-ready projects – a mindset that aligns perfectly with your expressed interest in wanting possible modular architecture for Google Workspace.

@zyeloncomputech

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@alluankit01

Hi, I can design and deploy your secure multi-tenant SMTP Gateway on AWS with Microsoft 365 Exchange Online Connector integration, TLS, Postfix, DLP inspection workflow, queues, logging, DNS security, and deployment documentation. The best solution is to first review your DLP API flow, tenant model, M365 connector requirements, TLS certificate strategy, DNS setup, and expected mail volume. Then I’ll configure an AWS EC2-based SMTP gateway, secure Postfix against open relay risks, identify tenants by connector/certificate/sender domain, inspect emails synchronously through the DLP engine, and allow or reject messages with correct SMTP responses. I’m comfortable with AWS EC2, Linux, Postfix, SMTP/ESMTP, TLS, Microsoft 365 connectors, SPF/DKIM/DMARC/PTR, queue management, logging, monitoring, email security, multi-tenant SaaS architecture, and DLP gateway integration. Deliverables will include: * AWS SMTP Gateway setup * Postfix secure relay configuration * Microsoft 365 connector setup * TLS and DNS configuration * Tenant identification design * Synchronous DLP inspection flow * Allow/block SMTP response handling * Queue, retry, and logging setup * Monitoring and health checks * DKIM/SPF/DMARC guidance * Architecture diagram * Deployment documentation * End-to-end testing support I’ll focus on security, tenant isolation, deliverability, and clean documentation so the gateway is production-ready and scalable for future Google Workspace support. Best regards Ankit

@kader307

Hi there, I see you need a specialist to design a secure, scalable multi-tenant SMTP Gateway integrated with Microsoft 365 Exchange Online, including SPF, DKIM, DMARC, IP reputation management, TLS certificates, partner connectors, and DLP-based mail inspection. I specialize in Linux server administration, SMTP infrastructure, Postfix, email authentication, DNS, TLS, and email deliverability, making this a strong fit. To answer your specific requirements: 1. I have 6+ years of experience working with Linux/POSIX systems, SMTP relays, Postfix, DNS, SPF, DKIM, DMARC, SSL/TLS certificates, email routing, and deliverability troubleshooting. 2. I have configured SMTP relays, email authentication records, DKIM signing, Office 365 mail settings, DNS records, TLS certificates, and secure email delivery workflows. 3. I will propose a secure AWS-based architecture with scalable SMTP relay nodes, centralized tenant configuration, encrypted secret storage, message queues, monitoring, and logs. 4. I can configure TLS client certificates and Exchange Online TLS partner connectors so messages are securely relayed only after your DLP application completes synchronous inspection. 5. I can start immediately and provide regular updates, architecture diagrams, deployment guides, and testing documentation. Before we start, do you have an existing DLP API/specification and preferred AWS services, or would you like me to propose the complete architecture? Best regards, Abdul Kader

@ravikumarsingh1

I have experience designing and deploying secure email infrastructure on AWS, including Postfix, Amazon SES, EC2, Linux administration, Microsoft 365 integrations, DNS (SPF, DKIM, DMARC), TLS, and email security. You can check my profile for similar SMTP, email server, and cloud infrastructure projects. For your requirements, I recommend Postfix as the SMTP Gateway due to its security, performance, flexibility, and support for milter/content filters, making it ideal for synchronous DLP inspection and future multi-tenant scaling. My proposed solution includes: • AWS EC2-based SMTP Gateway with Postfix • Microsoft 365 Exchange Online Connector integration • TLS partner authentication with certificate-based validation • Multi-tenant architecture with tenant configuration stored in PostgreSQL • Synchronous DLP inspection using a Milter or policy service before SMTP acceptance • Secure queue management, logging, monitoring, and health checks • SPF, DKIM, DMARC, PTR, and IP reputation best practices • Architecture documentation, deployment guide, and knowledge transfer Deliverables: ✔ Production-ready SMTP Gateway ✔ Multi-tenant architecture ✔ Microsoft 365 integration ✔ DLP integration interface ✔ Monitoring and security hardening ✔ Documentation and architecture diagrams ✔ End-to-end testing and handover I'm available to discuss the architecture, NDA requirements, timeline, and post-deployment support.

@mahads31

As an experienced Linux administrator, I have gained substantial skills in deploying secure, scalable, multi-tenant SMTP Gateways and would be a superb fit for your project. Smoothing the email routing process for multiple enterprise customers is a challenge that I relish in tackling. Regarding security measures, the majority of my projects involve implementing top-tier security protocols to prevent unauthorized access or abuse. Drawing from this experience, I will work with an extra layer of caution to ensure high security standards for your data-loss prevention system. Additionally, while many freelancers can complete this task on a small scale, my skills in deploying highly accessible and future-scalable solutions allow me to propose sophisticated solutions for implementation and potential Google Workspace integration. Choosing me means not only getting an expert who has proven themselves competent but also having someone committed to building a long-term relationship with you. I value clear communication and have a meticulous approach to documentation. I am excited about the possibility of transforming your ideas into a high-impact digital system that resolves all your DLP needs while aligning perfectly with your preferred email client, Microsoft Office 365.

@ibrahim0135

I’m a Cyber Security and Cloud Engineer with experience in AWS, Linux administration, Microsoft 365, secure email infrastructure, and enterprise security solutions. I have worked with Postfix, SMTP/TLS, DNS (SPF, DKIM, DMARC), Exchange Online, and secure mail routing, making me well-suited for designing and deploying your multi-tenant SMTP Gateway. My proposed solution uses Postfix on AWS EC2 with certificate-based Exchange Online Connectors, synchronous DLP inspection during the SMTP transaction using a milter or policy service, secure tenant identification, centralized configuration storage, comprehensive logging and monitoring, and a modular architecture that can be extended to Google Workspace in the future. The solution will include secure relay, queue management, monitoring, HA-ready architecture, DKIM strategy recommendations, detailed deployment documentation, architecture diagrams, end-to-end Microsoft 365 testing, and post-deployment knowledge transfer. I am available to start immediately, can sign an NDA, and provide ongoing support after deployment. I would be happy to discuss the architecture and implementation approach in more detail.

@toxicpuru

Hello, I have extensive experience designing and deploying Postfix-based SMTP infrastructure and email management platforms for high-volume, secure email delivery. I can build a scalable SMTP gateway on AWS (or your preferred platform), configure SPF, DKIM, DMARC, TLS, and IP reputation management, and integrate it securely with Microsoft 365 Exchange Online using partner connectors and authenticated TLS where required. I've also implemented MailWizz-based email management solutions, enabling centralized campaign management, sender management, throttling, bounce processing, tracking, and multi-domain/multi-tenant email operations. This combination provides a robust, scalable email infrastructure that is easy to manage while maintaining strong deliverability. My approach focuses on secure architecture, tenant isolation, scalable configuration management, proper DNS authentication, IP warm-up/reputation management, comprehensive documentation, and smooth integration with your existing DLP workflow. I'm available to start immediately and would be happy to discuss the architecture that best fits your requirements. Best regards, Purushottam Kumar

@MQamar123

For the demanding task of designing and deploying a secure, scalable and multi-tenant SMTP Gateway on AWS that integrates with M365 Exchange Online, I bring to the table over 7 years of versatile experience in software development, cloud computing and REST/SOAP APIs. My knowledge encompasses essential areas like AWS EC2, SMTP, ESMTP, TLS, Linux administration, DNS (SPF, DKIM, DMARC, PTR) with expertise in Postfix. Having worked extensively with DLP products and email infrastructure in the past, I understand how they interact and can provide seamless integration with your DLP application through API or any recommended approach for optimal functionality. To sum it up, considering my extensive skill set and proven ability to deliver successful end-to-end projects within set deadlines, choosing me for this job will be a decision you won't regret. I assure you of the meticulous deployment of an efficient solution; providing not only production-ready SMTP Gateway deployed on AWS but also mentoring knowledge transfer session for your in-house team.

@Appworldz

Hi, I’ve designed secure SMTP relay and email gateway solutions integrating Microsoft 365 Exchange Online with SPF, DKIM, DMARC, TLS partner connectors, IP reputation management, and AWS based infrastructure. I can deliver a scalable multi tenant architecture with secure routing, DLP integration, tenant isolation, certificate management, and complete deployment documentation. For this enterprise scope, I recommend ₹180,000 to ₹250,000 with a 4 to 6 week timeline, as the posted budget is well below the effort required for a production grade email gateway. Sahanaj

@SimCodec

Hi, designing a multi-tenant SMTP gateway that handles synchronous DLP inspection requires strict handling of SMTP state machines to ensure the transaction timing aligns with M365's timeout limits. We would implement this using a containerized Postfix or Exim cluster orchestrated on AWS, leveraging high-performance queues to maintain low latency during the DLP handshake. By utilizing custom milter scripts, we can ensure the gateway holds the DATA command until the DLP engine provides a verdict. How are you currently planning to manage the TLS certificate distribution and rotation for each unique tenant domain? The SimCodec Team

@rakhshanz3

As a seasoned computer scientist and AI professional with a wide range of experience, I understand the inextricable connection between system design and practical implementation. I am uniquely positioned to create an SMTP Gateway solution for you that is both robust and scalable on AWS, while ensuring seamless integration with Microsoft 365 Exchange Online Connectors. My extensive expertise in Linux administration, AWS EC2, SMTP routing, TLS communication, and email security best practices align perfectly with this project's requirements. Furthermore, I bring to the table a comprehensive understanding of DNS configuration as well as email routing and queue management—an invaluable asset in configuring your SMTP Gateway to run smoothly under high performance demands. With hands-on experience deploying secure email gateways and managing similar email infrastructures, I fully appreciate the seriousness of data loss prevention measures.