Centralized Cross-Account File Exchange Platform Using AWS Transfer Family

The client is a large enterprise with multiple business units, each operating in its own AWS environment for regulatory and billing purposes. They needed a unified...

[Overview] System Overview

Ampity Infotech deployed a centralized Cross-Account File Transfer solution using AWS Transfer Family. This Hub-and-Spoke architecture allows the client to manage a single secure entry point for all external partners while ensuring data is automatically and securely routed to Amazon S3 buckets located in separate, isolated AWS accounts.

[Targets] The Goals

[Constraints] The Challenges

[Strategy] Our Solution

[DESIGN] Architecture design

multi-account-transfer-family

[APPROACH] Execution model

##### Cross-Account IAM Design

Defined the Trust Relationships and IAM Policies required for the Hub account to access Spoke buckets.

##### Target Bucket Configuration

Applied Bucket Policies in destination accounts (Account B, C, etc.) to allow write access from the Hub.

##### Service Deployment

Provisioned the AWS Transfer Family endpoint in the Hub Account.

##### User Mapping

Configured logical home directories pointing to cross-account S3 URIs.

##### Ownership Enforcement

Configured Object Ownership settings to ensure destination accounts own the incoming data.

##### Validation

Verified end-to-end connectivity and file accessibility from the destination accounts.

[RESULTS] Measurable outcomes

##### Scalability

The central endpoint scales to support traffic for all business units simultaneously.

##### Performance

Cross-account network latency is negligible within the same AWS Region.

##### Security

Enforced strict least-privilege access across account boundaries.

##### Availability

Centralized endpoint maintains 99.99% uptime availability.

##### Cost Optimization

Centralized resource sharing significantly lowered the cost per GB transferred.

##### Operational Efficiency

Reduced administrative workload by managing 1 endpoint instead of N endpoints.

[TOOLS] Technology Stack

AWS Transfer Family (Central Hub)

Amazon S3 (Cross-Account Targets)

AWS IAM (Cross-Account Roles)

KMS

Amazon CloudWatch Logs

Amazon VPC

Security Groups

Amazon Route 53

Terraform

[ANTI-PATTERNS] What could have gone wrong

##### Benefits

Unified Governance: A single pane of glass for monitoring and managing all corporate file transfers.

Cost Consolidation: Removed the need to pay for idle SFTP resources in every single business unit account.

Data Sovereignty: Data never resides in the central account; it streams directly to the secure, isolated destination bucket.

Simplified Onboarding: Partners only need to whitelist one IP address/domain, regardless of which business unit they are sending data to.

Security Compliance: Centralized logging ensures a complete audit trail of all movements across accounts.

[APPLICABILITY] Where this pattern applies

Streamlined B2B operations by providing a consistent interface for all external partners.

Reduced TCO by ~50% through infrastructure consolidation.

Eliminated Shadow IT where individual teams were spinning up unmanaged FTP servers.

Ensured compliance with internal data isolation policies while maintaining operational agility.