Q: What is AWS Transfer Family?
A: The AWS Transfer Family offers fully managed support for the transfer of files over SFTP, FTPS, and FTP directly into and out of Amazon S3 or Amazon EFS. You can seamlessly migrate, automate, and monitor your file transfer workflows by maintaining existing client-side configurations for authentication, access, and firewalls — so nothing changes for your customers, partners, and internal teams, or their applications.
Q: What is SFTP?
A: SFTP stands for Secure Shell (SSH) File Transfer Protocol, a network protocol used for secure transfer of data over the internet. The protocol supports the full security and authentication functionality of SSH, and is widely used to exchange data between business partners in a variety of industries including financial services, healthcare, media and entertainment, retail, advertising, and more.
Q: What is FTP?
A: FTP stands for File Transfer Protocol, a network protocol used for the transfer of data. FTP uses a separate channel for control and data transfers. The control channel is open until terminated or inactivity timeout, the data channel is active for the duration of the transfer. FTP uses cleartext and does not support encryption of traffic.
Q: What is FTPS?
A: FTPS stands for File Transfer Protocol over SSL, and is an extension to FTP. It uses Transport Layer Security (TLS) and Secure Sockets Layer (SSL) cryptographic protocols to encrypt traffic. FTPS allows encryption of both the control and data channel connections either concurrently or independently.
Q: Why should I use the AWS Transfer Family?
A: AWS Transfer Family supports multiple protocols for business-to-business (B2B) file transfers so data can easily and securely be exchanged across stakeholders, third-party vendors, business partners, or customers. Without using Transfer Family, you have to host and manage your own file transfer service which requires you to invest in operating and managing infrastructure, patching servers, monitoring for uptime and availability, and building one-off mechanisms to provision users and audit their activity. The AWS Transfer Family solves these challenges by providing fully managed support for SFTP, FTPS, and FTP that can reduce your operational burden, while preserving your existing transfer workflows for your end users. AWS Transfer Family’s managed file-processing workflows, enables you to create, automate, and monitor your file transfer and data processing without maintaining your own code or infrastructure. The service stores transferred data as objects in your Amazon S3 bucket or as files in your Amazon EFS file system, so you can extract value from them in your data lake, or for your Customer Relationship Management (CRM) or Enterprise Resource Planning (ERP) workflows, or for archiving in AWS.
Q: What are the benefits of using the AWS Transfer Family?
A: The AWS Transfer Family provides you with a fully managed, highly available file transfer service with auto-scaling capabilities, eliminating the need for you to manage file transfer related infrastructure. Your end users’ workflows remain unchanged, while data uploaded and downloaded over the chosen protocols is stored in your Amazon S3 bucket or Amazon EFS file system. With the data in AWS, you can now easily use it with the broad array of AWS services for data processing, content management, analytics, machine learning, and archival, in an environment that can meet your compliance requirements.
Q: How do I use the AWS Transfer Family?
A: In 3 simple steps, you get an always-on server endpoint enabled for SFTP, FTPS, and/or FTP. First, you select the protocol(s) you want to enable your end users to connect to your endpoint. Next, you configure user access using Transfer Family’s built-in authentication manager (service managed), Microsoft Active Directory (AD), or by integrating your own or a third party identity provider such as Okta or Microsoft AzureAD (“BYO” authentication). Finally, select the server to access S3 buckets or EFS file systems. Once the protocol(s), identity provider, and the access to file systems are enabled, your users can continue to use their existing SFTP, FTPS, or FTP clients and configurations, while the data accessed is stored in the chosen file systems.
Q: What is the difference between SFTP and FTPS? Which should I use when?
A: FTPS and SFTP can both be used for secure transfers. Since they are different protocols, they use different clients and technologies to offer a secure tunnel for transmission of commands and data. SFTP is a newer protocol and uses a single channel for commands and data, requiring fewer port openings than FTPS.
Q: Can my users continue to use their existing file transfer clients and applications?
A: Yes, any existing file transfer client application will continue to work as long as you have enabled your endpoint for the chosen protocols. Examples of commonly used clients include WinSCP, FileZilla, CyberDuck, lftp, and OpenSSH clients.
Q: Can I use CloudFormation to automate deployment of my servers and users?
A: Yes, you can deploy CloudFormation templates to automate creation of your servers and users or for integrating an identity provider. Refer to the usage guide for using AWS Transfer resources in CloudFormation templates.
Q: Can my users use SCP, HTTPS, or AS2 to transfer files using this service?
A: No, your users will need to use SFTP, FTPS, or FTP to transfer files. Most file transfer clients offer either of these protocols as an option that will need to be selected during authentication. Please let us know via AWS Support or through your AWS account team of any specific protocols you would like to see supported.
Server endpoint options
Q: Can I use my corporate domain name (sftp.mycompanyname.com) to access my endpoint?
A: Yes. If you already have a domain name, you can use Amazon Route 53 or any DNS service to route your users’ traffic from your registered domain to the server endpoint in AWS. Refer to the documentation on how the AWS Transfer Family uses Amazon Route 53 for custom domain names (applicable to internet facing endpoints only).
Q: Can I still use the service if I don’t have a domain name?
A: Yes, if you don’t have a domain name, your users can access your endpoint using the hostname provided by the service. Alternatively, you can register a new domain using the Amazon Route 53 console or API, and route traffic from this domain to the service supplied endpoint hostname.
Q: Can I use my domain that already has a public zone?
A: Yes, you will need to CNAME the domain to the service supplied endpoint hostname.
Q: Can I set up my server to be accessible to resources only within my VPC?
A: Yes. When you create a server or update an existing one, you have the option to specify whether you want the endpoint to be accessible over the public internet or hosted within your VPC. By using a VPC hosted endpoint for your server, you can restrict it to be accessible only to clients within the same VPC, other VPCs you specify, or in on-premises environments using networking technologies that extend your VPC such as AWS Direct Connect, AWS VPN, or VPC peering. You can further restrict access to resources in specific subnets within your VPC using subnet Network Access Control Lists (NACLs) or Security Groups. Refer to the documentation on creating your server endpoint inside your VPC using AWS PrivateLink for details.
Q: Can I use FTP with an internet facing endpoint?
A: No, when you enable FTP, you will only be able to use VPC hosted endpoint‘s internal access option. If traffic needs to traverse the public network, secure protocols such as SFTP or FTPS should be used.
Q: What if I need to use FTP for transfers over the public internet?
A: The service doesn’t allow you to use FTP over public networks because, when you create a server enabled for FTP, the server endpoint is only accessible to resources within your VPC. If you need to use FTP for exchanging data over the public internet, you can front your server’s VPC endpoint with an internet-facing Network Load Balancer (NLB). To support FTP clients that may not work with this configuration, use your server in PASV mode.
Q: Can I use FTP without a VPC?
A: No. VPC is required to host FTP server endpoints. Please refer to the documentation for CloudFormation templates to automate creation of VPC resources to host the endpoint during server creation.
Q: Can my end users use fixed IP addresses to allowlist access to my server’s endpoint in their firewalls?
A: Yes. You can enable fixed IPs for your server endpoint by selecting the VPC hosted endpoint for your server and choosing the internet-facing option. This will allow you to attach Elastic IPs (including BYO IPs) directly to the endpoint, which is assigned as the endpoint’s IP address. Refer to the section on creating an internet facing endpoint in the documentation: Creating your server endpoint inside your VPC.
Q: Can I restrict incoming traffic by end users’ source IP addresses?
A: Yes. You have three options to restrict incoming traffic by users’ source IP address. If you are hosting your server endpoint within VPC, refer to this blog post on using Security Groups to allow list source IP address or use AWS Network Firewall service. If you are a public EndpointType Transfer server and API Gateway to integrate your identity management system, you can also use AWS WAF to allow, block, or rate limit access by your end users’ Source IP address.
Q: Can I host my server’s endpoint in a shared VPC environment?
A: Yes. You can deploy your server endpoint with shared VPC environments typically used when segmenting your AWS environment using tools such as AWS Landing Zone for security, cost monitoring, and scalability. Refer to this blog post on using VPC hosted endpoints in shared VPC environments with AWS Transfer Family.
Q: How do I access files stored in an external SFTP or FTPS site?
A: Refer to this blog post on using AWS Fargate to connect to an external SFTP/FTPS site and access your data using AWS Transfer Family. If you are looking for a fully managed solution for connecting to external sites, reach out to us via AWS Support or through your AWS account team.
Q: How do I improve performance of file transfers for remotely located end users?
A: You can use AWS Global Accelerator with your Transfer server endpoint to improve file transfer throughput and round-trip time. Visit this blog post for more information.
Q: Can I select which cryptographic algorithms can be used when my end users’ clients connect to my server endpoint?
A: Yes, Based on your security and compliance requirements, you can select one of three security policies to control the cryptographic algorithms that will be advertised by your server endpoints: Transfer-Security-Policy-2018-11 (default), Transfer-Security-Policy-2020-06 (restrictive – No SHA-1 algorithms), and Transfer-FIPS-2020-06 (FIPS compliant algorithms). When your end users’ file transfer clients attempt to connect to your server, only the algorithms specified in the policy will be used to negotiate the connection. Refer to the documentation on pre-defined security policies.
Q: Can my end users use fixed IP addresses to access my server whose endpoint type is PUBLIC?
A: No. Fixed IP addresses that are usually used for firewall whitelisting purposes are currently not supported on the PUBLIC Endpoint type. Use VPC hosted endpoints to assign static IP addresses for your endpoint.
Q: What IP ranges would my end users need to whitelist to access my SFTP server’s endpoint type that is PUBLIC?
A: If you are using the PUBLIC endpoint type, your users will need to whitelist the AWS IP address ranges published here. Refer to the documentation for details on staying up to date with AWS IP Address Ranges.
Q: Will my AWS Transfer for SFTP server's host key ever change after I create the server?
A: No. The server’s host key that is assigned when you create the server remains the same, until you delete and create a new one.
Q: Can I import keys from my current SFTP server so my users do not have to reverify the session information?
A: Yes. You can provide a RSA host key when you create a new server, or update an existing one. This key will be used by your end users’ clients to identify your server. Refer to the documentation on using the AWS CLI/SDKs for uploading a Host Key for your server.
Q: How do my end users’ FTPS clients verify the identity of my FTPS server?
A: When you enable FTPS access, you will need to supply a certificate from Amazon Certificate Manager (ACM). This certificate is used by your end user clients to verify the identity of your FTPS server. Refer to the ACM documentation on Requesting New certificates or importing existing certificates into ACM.
Q: Do you support active and passive modes of FTPS and FTP?
A: We only support passive mode, which allows your end users’ clients to initiate connections with your server. Passive mode requires fewer port openings on the client side, making your server endpoint more compatible with end users behind protected firewalls.
Q: Do you support Explicit and Implicit FTPS modes?
A: We only support explicit FTPS mode.
Q: Can I transfer files over FTPS/FTP protocols if I have a firewall or a router configured between the client and the server?
A: Yes. File transfers traversing a firewall or a router are supported by default using extended passive connection mode (EPSV). If you are using an FTPS/FTP client that does not support EPSV mode, visit this blog post to configure your server in PASV mode to expand your server’s compatibility to a broad range of clients.
Q: Can I enable multiple protocols on the same endpoint?
Yes. During setup, you can select the protocol(s) you want to enable for clients to connect to your endpoint. The server hostname and identity provider are shared across the selected protocols. Similarly, you can also add FTP/FTPS support to an existing AWS Transfer for SFTP server endpoint, as long as the endpoint is hosted within your VPC and you are using a Custom Identity Provider.
Q: When should I create separate server endpoints for each protocol vs enable the same endpoint for multiple protocols?
A: When you need to use FTP (only supported for access within VPC), and also need to support over the internet for SFTP or FTPS, you will need a separate server endpoint for FTP. You can use the same endpoint for multiple protocols, when you want to use the same endpoint hostname and IP address for clients connecting over multiple protocols. Additionally, if you want to share the same credentials for SFTP and FTPS, you can set up and use a single identity provider for authenticating clients connecting over either protocol.
Q: Can I set up the same end user to access the endpoint over multiple protocols?
A: Yes, you can provide the same user access over multiple protocols, as long as the credentials specific to the protocol have been set up in your identity provider. If you have enabled FTP, we recommend maintaining separate credentials for FTP. Refer to the documentation for setting up separate credentials for FTP.
Q: Why should I maintain separate credentials for FTP users?
A: Unlike SFTP and FTPS, FTP transmits credentials in cleartext. We recommend isolating FTP credentials from SFTP or FTPS because, if, inadvertently FTP credentials are shared or exposed, your workloads using SFTP or FTPS remain secure.
Q: Can my users access AWS Transfer Family’s SFTP endpoint using a browser?
A: Yes, you can deploy this open-source solution that enables you to provide a browser-based interface using your AWS Transfer Family’s SFTP endpoints.
Identity Provider options
Q: What identity provider options are supported by the service?
A: The service supports three identity provider options: Service Managed, where you store user identities within the service, Microsoft Active Directory, and, Custom options (BYO), which enable you to integrate an identity provider of your choice. Service Managed authentication is supported for server endpoints that are enabled for SFTP only.
Q: How can I authenticate my users using Service Managed authentication?
A: You can use Service Managed authentication to authenticate your SFTP users using SSH keys.
Q: How many SSH keys can I upload per SFTP user?
A: You can upload up to 10 SSH keys per user.
Q. Is SSH key rotation supported for service managed authentication?
A: Yes. Refer to the documentation for details on how to set up key rotation for your SFTP users.
Q. Can I use service managed option for password authentication?
A: No, storing passwords within the service for authentication is currently not supported. If you need password authentication, use Active Directory by selecting a directory in AWS Directory Service, or follow the architecture described in this blog on Enabling Password Authentication using Secrets Manager.
Q: How do I get started with using Microsoft AD?
A: When you create your server, you select a directory in AWS Managed Microsoft AD, your on-premises environment, or self-managed AD in Amazon EC2 as your identity provider. You will then need to specify the AD Groups you want to enable for access using a Security Identifier (SID). Once you associate your AD group with access control information such as IAM Role, scope down policy (S3 only), POSIX Profile (EFS only), home directory location, and logical directory mappings, members of the group can use their AD credentials to authenticate and transfer files over the enabled protocols (SFTP, FTPS, FTP).
Q: How can I set up my AD users so they have isolated access to different parts of my S3 bucket?
A: When you set up your users, you supply a scope down policy that is evaluated in run time based on your users’ information such as their username. You can use the same scope down policy for all your users to provide access to unique prefixes in your bucket based on their username. Additionally, a username can also be used to evaluate logical directory mappings by providing a standardized template on how your S3 bucket or EFS file system contents are made visible to your user. Visit the documentation to Grant Access to AD Groups.
Q: Can I use Microsoft AD as an identity provider option for all the supported protocols?
A: Yes, you can use Microsoft AD to authenticate users for access over SFTP, FTPS, and FTP.
Q: Can I revoke access for enabled AD groups?
A: Yes, you can revoke file transfer access for individual AD Groups. Once revoked, members of the AD groups will not be able to transfer files using their AD credentials.
Q: Can I provide access to individual AD users or to all users in a directory?
A: No, we only support setting access by AD Groups.
Q: Can I use AD to authenticate users using SSH keys?
A: No, AWS Transfer Family support for Microsoft AD can only be used for password based authentication. To use a mix of authentication modes, use the Custom authorizer option.
Q. Why should I use the Custom authentication mode?
A: The Custom mode (“BYO” authentication) enables you to leverage an existing identity provider to manage your end users for all protocol types (SFTP, FTPS, and FTP), enabling easy and seamless migration of your users. Credentials can be stored in your corporate directory or an in-house identity datastore, and you can integrate it for end user authentication purposes. Examples of identity providers include Okta, Microsoft AzureAD, or any custom-built identity provider you may be using as a part of an overall provisioning portal.
Q. How can I get started with integrating my existing identity provider for Custom authentication?
A: To get started, you can use the AWS CloudFormation template in the usage guide and supply the necessary information for user authentication and access. Visit the website on custom identity providers to learn more.
Q: When setting up my users via a custom identity provider, what information is used to enable access to my users?
A: Your user will need to provide a username and password (or SSH key) which will be used to authenticate, and access to your bucket is determined by the AWS IAM Role supplied by the API Gateway and Lambda used to query your identity provider. You will also need to provide home directory information, and it is recommended that you lock them down to the designated home folder for an additional layer of security and usability. Refer to this blog post on how to simplify your end users’ experience when using a custom identity provider with AWS SFTP.
Q. Are anonymous users supported?
A: No, anonymous users are currently not supported for any of the protocols.
Managed workflows for post upload processing
Q: What is managed workflows for post upload processing?
A: AWS Transfer Family support for managed workflows makes it easier for you to create, execute, and monitor post upload processing for file transfers over SFTP, FTPS, and FTP. Using this feature, you can save time with low code automation to coordinate all the necessary tasks such as copying and tagging. You can also customize to scan for PII, virus/malware, or other errors such as incorrect file format or type, enabling you to quickly detect anomalies and meet your compliance requirements.
Q: Why do I need managed workflows?
A: When exchanging data with your business partners over one of the available AWS Transfer Family protocols (SFTP, FTPS, FTP) that needs pre-processing, you have to configure multiple settings including, setting up an infrastructure to run custom code upon file arrival; writing your own tagging and copying functions; continuously monitor the run time for errors and anomalies; and make sure all changes and transformations to the data are audited and logged. Additionally, you need to account for error scenarios, both technical and business, while ensuring failsafe modes are properly triggered. If you have requirements for traceability, you need to track lineage of the data as it passes along different components of your workflow. Maintaining and managing these types of workflows takes time away from focusing on differentiating work you could be doing for your business. With AWS Transfer Family managed workflows these tedious tasks are taken care of from the start.
Q: What are the benefits of using workflows?
Using AWS Transfer Family’s managed workflows, you can orchestrate common file processing steps such as copying and tagging, without the overhead of managing your own custom code and infrastructure. Additionally, AWS Transfer Family’s managed workflows allows you to bring your own file processing logic using AWS Lambda for use cases such as malware scanning and file-type compatibility check, enabling you to easily pre-process data before feeding it to your data analytics pipelines. You get full visibility into your workflow executions using AWS Transfer Family Management Console and Amazon CloudWatch logs for robust monitoring and alerting systems.
Q: How do I get started with workflows?
A: First, set-up your workflow to contain actions such as copying, tagging, and a series of actions that can include your own custom step in a sequence of steps based on your requirements. Next, map the workflow to a server, so on file arrival, actions specified in this workflow are evaluated and triggered in real-time. Refer to the documentation for more details.
Q: Can I use the same workflow set-up across multiple servers?
A: Yes. The same workflow can be assigned to multiple servers so it is easier for you to maintain and standardize configurations.
Q: What actions can I take on my files using workflows?
A: The following common actions are available once a transfer server has received a file from the client:
- Move or copy data from where it arrives to where it needs to be consumed.
- Tag the file based on its contents so it can be indexed and searched by downstream services (S3 only)
- Any custom file processing logic by supplying your own Lambda function as a custom step to your workflow. For example, checking compatibility of the file type, scanning files for malware, and metadata extraction before ingesting files to your data analytics.
Q: How do I view status of my workflows?
A: Using the AWS Management Console, you can search and view real-time status of in progress Workflow executions. CloudWatch logs for your server will provide details on completed executions as well.
Q: What types of notifications can I receive?
A: You can use the custom processor step to trigger notifications to EventBridge and get notified when a file has completed processing. Additionally, you can also use CloudWatch logs from Lambda executions to get notifications.
Q: I am using AWS Step Functions to orchestrate my file-processing steps. How do AWS Transfer Family’s managed workflows differ from my current AWS Step Functions set up?
A: AWS Step Functions is a serverless orchestration service that lets you combine AWS Lambda with other services to define the execution of business application in simple steps. To perform file-processing steps using AWS Step Functions, you use AWS Lambda functions with Amazon S3’s event triggers to assemble your own workflows. Managed workflows provide a framework to easily orchestrate a linear sequence of processing and differentiates from existing solutions in the following ways: 1) Only full file uploads trigger workflows to be executed, 2) workflows can be triggered automatically for S3 as well as EFS (which doesn’t offer post upload events), and 3) customers can get end to end visibility into their file transfers and processing in CloudWatch logs.
Q: Can I send a notification if a file validation check fails?
A: Yes. If a file validation check fails against preconfigured validation steps, you can use the exception handler to invoke your monitoring system or team members via Amazon SNS topic.
Q: Can I trigger workflow actions on user downloads?
A: No. Processing can be invoked only on file arrival using the inbound endpoint.
Q: Can I trigger the same workflow on batches of files in a session?
Q: Can workflows be triggered on partial uploads?
A: No. Only completed and full file uploads will trigger processing by workflows.
Amazon S3 Access
Q: Why do I need to provide an AWS IAM Role and how is it used?
A: AWS IAM is used to determine the level of access you want to provide your users. This includes the operations you want to enable on their client and which Amazon S3 buckets they have access to – whether it’s the entire bucket or portions of it.
Q: Why do I need to provide home directory information and how is it used?
A: The home directory you set up for your user determines their login directory. This would be the directory path that your user’s client will place them in as soon as they are successfully authenticated into the server. You will need to ensure that the IAM Role supplied provides user access to the home directory.
Q: I have 100s of users who have similar access settings but to different portions of my bucket. Can I set them up using the same IAM Role and policy to enable their access?
A: Yes. You can assign a single IAM Role for all your users and use logical directory mappings that specify which absolute Amazon S3 bucket paths you want to make visible to your end users and how you these paths presented to them by their clients. Visit this blog on how to 'Simplify Your AWS SFTP/FTPS/FTP Structure with Chroot and Logical Directories'.
Q: How are files stored in my Amazon S3 bucket transferred using AWS Transfer?
A: Files transferred over the supported protocols are stored as objects in your Amazon S3 bucket, and there is a one-to-one mapping between files and objects enabling native access to these objects using AWS services for processing or analytics.
Q: How are Amazon S3 objects stored in my bucket presented to my users?
A: After successful authentication, based on your users’ credentials, the service presents Amazon S3 objects and folders as files and directories to your users’ transfer applications.
Q: What file operations are supported? What operations are not supported?
A: Common commands to create, read, update, and delete, files and directories are supported. Files are stored as individual objects in your Amazon S3 bucket. Directories are managed as folder objects in S3, using the same syntax as the S3 console.
Directory rename operations, append operations, changing ownerships, permissions and timestamps, and use of symbolic and hard links are currently not supported.
Q: Can I control which operations my users are allowed to perform?
A: Yes, you can enable/disable file operations using the AWS IAM role you have mapped to their username. Refer to the documentation on 'Creating IAM Policies and Roles to control your end users’ access
Q: Can I provide my end users access to more than one Amazon S3 bucket?
A: Yes. The bucket(s) your user can access is determined by the AWS IAM Role, and the optional scope-down policy you assign for that user. You can only use a single bucket as the home directory for the user.
Q: Can I create a server using AWS Account A and map my users to Amazon S3 buckets owned by AWS Account B?
A: Yes. You can use the CLI and API to set up cross account access between your server and the buckets you want to use for storing files transferred over the supported protocols. The Console drop down will only list buckets in Account A. Additionally, you’d need to make sure the role being assigned to the user belongs to Account A.
Q: Can I automate processing of a file once it has been uploaded to Amazon S3?
A: Yes, you can use AWS Transfer Family’s managed workflows to create, automate, and monitor file processing after your files are uploaded to Amazon S3. Using managed workflows, you can pre-process your files before ingesting them to your data analytics and processing systems, without the overhead of managing your own custom code and infrastructure. Visit the documentation to learn about AWS Transfer Family’s managed workflows.
Q: Can I customize rules for processing based on the user uploading the file?
A: Yes. When your user uploads a file, the username and the server id of the server used for the upload is stored as part of the associated S3 object’s metadata. You can use this information for post upload processing. Refer to the documentation on information you use for post upload processing.
Amazon EFS Access
Q: How do I set up my EFS file system to work with AWS Transfer Family?
A: Prior to setting up AWS Transfer Family to work with an Amazon EFS file system, you will need to set up ownership of files and folders using the same POSIX identities (user id/group id) you plan to assign to your AWS Transfer Family users. Additionally, if you are accessing file systems in a different account, resource policies must also be configured on your file system to enable cross account access.
Q: How do I provide access to my users to upload/download files to/from my file systems?
A: Amazon EFS uses POSIX IDs which consist of an operating system user id, group id, and secondary group id to control access to a file system. When setting up your user in the AWS Transfer Family console/CLI/API, you will need to specify the username, user’s POSIX configuration, and an IAM role to access the EFS file system. You will also need to specify an EFS file system id and optionally a directory within that file system as your user’s landing directory. When your AWS Transfer Family user authenticates successfully using their file transfer client, they will be placed directly within the specified home directory, or root of the specified EFS file system. Their operating system POSIX id will be applied to all requests made through their file transfer clients. As an EFS administrator, you will need to make sure the file and directories you want your AWS Transfer Family users to access are owned by their corresponding POSIX ids in your EFS file system. Refer to the documentation to learn more on configuring ownership of sub-directories in EFS.
Q: How are files transferred over the protocols stored in my Amazon EFS file systems?
A: Files transferred over the enabled protocols are directly stored in your Amazon EFS file Systems and will be accessible via a standard file system interface or from AWS services that can access Amazon EFS file systems.
Q: What file operations are supported over the protocols when using Amazon S3 and Amazon EFS?
A: SFTP/FTPS/FTP commands to create, read, update, and delete files, directories, and symbolic links are supported. Refer to the table below on supported commands for EFS as well as S3.
|Command||Amazon S3||Amazon EFS|
|get||Supported||Supported including resolving symlinks and hardlinks|
|ln -s/symlink||Not supported||Supported|
1 Only file renames are supported. Directory renames and rename of files to overwrite existing files are not supported.
2 Only root i.e. users with uid=0 can change ownership and permissions of files and directories.
3 Supported either for root e.g. uid=0 or for the file’s owner who can only change a file’s group to be one of their secondary groups.
4 Supported for non-empty folders only.
Q: How can I control which files and folders my users have access to and which operations they are allowed to and not allowed to perform?
A: The IAM policy you supply for your AWS Transfer Family user determines if they have read-only, read-write, and root access to your file system. Additionally, as a file system administrator, you can set up ownership and grant to access files and directories within your file system using their user id and group id. This applies to users whether they are stored within the service (service managed) or within your identity management system (“BYO Auth”).
Q: Can I restrict each of my users to access different directories within my file system and only access files within those directories?
A: Yes, when you set up your user, you can specify different file systems and directories for each of your users. On successful authentication, EFS will enforce a directory for every file system request made using the enabled protocols.
Q: Can I hide the name of the file system from being exposed to my user?
A: Yes, using AWS Transfer Family’s logical directory mappings, you can restrict your end users’ view of directories in your file systems by mapping absolute paths to end user visible path names. This also includes being able to “chroot” your user to their designated home directory.
Q: Are symbolic links supported?
A: Yes, if symbolic links are present in directories accessible to your user and your user tries to access them, the links will be resolved to its target. Symbolic links are not supported when you use logical directory mappings to set up your users' access.
Q: Can I provide an individual SFTP/FTPS/FTP user access to more than one file system?
A: Yes, when you set up an AWS Transfer Family user, you can specify one or more file systems in the IAM policy you supply as part of your user set up in order to grant access to multiple file systems.
Q: What operating systems can I use to access my EFS file systems via AWS Transfer Family?
A: You can use clients and applications built for Microsoft Windows, Linux, macOS, or any operating system that supports SFTP/FTPS/FTP to upload and access files stored in your EFS file systems. Simply configure the server and user with the appropriate permissions to the EFS file system to access the file system across all operating systems.
Q: How do I automate and monitor file-processing steps after my file is uploaded to EFS?
A: You can create AWS Transfer Family’s managed workflow to automatically trigger file-processing after the file is uploaded to EFS. You can set up workflows that contain tagging, copying, any custom processing step that you would like to perform on the file based on your business requirement. Visit AWS Transfer Family’s managed workflow documentation to learn more.
Q: How do I know which user uploaded a file?
A: For new files, the POSIX user id associated with the user uploading the file will be set as the owner of the file in your EFS file system. Additionally, you can use Amazon CloudWatch to track your users’ activity for file creation, update, delete, and read operations. Visit the documentation to learn more on how to enable Amazon CloudWatch logging.
Q: Can I view how much data was uploaded and downloaded over the enabled protocols?
A: Yes, metrics for data uploaded and downloaded using your server are published to Amazon CloudWatch within the AWS Transfer Family namespace. Visit the documentation to view the available metrics for tracking and monitoring.
Q: Can I use AWS Transfer Family to access a file system in another account?
A: Yes. You can use the CLI and API to set up cross account access between your AWS Transfer Family resources and EFS file systems. The AWS Transfer Family console will only list file systems in the same account. Additionally, you’d need to make sure the IAM role assigned to the user to access the file system belongs to Account A.
Q: What happens if my EFS file system does not have the right policies enabled for cross account access?
A: If you set up an AWS Transfer Family server to access a cross account EFS file system not enabled for cross account access, your SFTP/FTP/FTPS users will be denied access to the file system. If you have CloudWatch logging enabled on your server, cross account access errors will be logged to your CloudWatch Logs.
Q: Can I use AWS Transfer Family to access an EFS file system in a different AWS Region?
A: No, you can use AWS Transfer Family to access EFS file systems in the same AWS Region only.
Q: Can I use AWS Transfer Family with all EFS storage classes?
A: Yes. You can use AWS Transfer to write files into EFS and configure EFS Lifecycle Management to migrate files that have not been accessed for a set period of time to the Infrequent Access (IA) storage class.
Q: Can my applications use SFTP/FTPS/FTP to concurrently read and write data from/to the same file?
A: Yes, Amazon EFS provides a file system interface, file system access semantics (such as strong consistency and file locking), and concurrently-accessible storage for up to thousands of NFS/SFTP/FTPS/FTP clients.
Q: Will my EFS burst credits be consumed when I access my file systems using AWS Transfer Family?
A: Yes. Accessing your EFS file systems using your AWS Transfer Family servers will consume your EFS burst credits regardless of the throughput mode. Refer to the documentation on available performance and throughput modes and view some useful performance tips.
Security and compliance
Q: Which protocols should I use for securing data while in-transit over a public network?
A: Either SFTP or FTPS should be used for secure transfers over public networks. Due to the underlying security of the protocols based on SSH and TLS cryptographic algorithms, data and commands are transferred through a secure, encrypted channel.
Q: What are my options to encrypt data at rest?
A: You can choose to encrypt files stored your bucket using Amazon S3 Server-Side Encryption (SSE-S3) or Amazon KMS (SSE-KMS). For files stored in EFS, you can choose AWS or customer managed CMK for encryption of files at rest. Refer to the documentation for more details on options for at rest encryption of file data and metadata using Amazon EFS.
Q: Which compliance programs does AWS Transfer Family support?
A: AWS Transfer Family is PCI-DSS and GDPR compliant, and HIPAA eligible. The service is also SOC 1, 2, and 3 compliant. Learn more about services in scope by compliance programs.
Q: Is AWS Transfer Family FISMA compliant?
A: AWS East/West and GovCloud (US) Regions are FISMA compliant. When AWS Transfer Family is authorized for FedRAMP, it will be FISMA compliant within the respective regions. This compliance is demonstrated through FedRAMP Authorization of these two regions to FedRAMP Moderate and FedRAMP High. We demonstrate compliance through annual assessments and documenting compliance with in-scope NIST SP 800-53 controls within our System Security Plans. Templates are available on Artifact along with our customer responsibility matrix (CRM) which demonstrates at a detailed level or responsibility to meet these NIST controls as required by FedRAMP. Artifact is available through the management console accessible by an AWS account for both East/West and GovCloud. If you have any further questions on this topic, please consult the Console.
Q: How does the service ensure integrity of uploaded files?
A: Files uploaded through services are verified by comparing the file’s pre- and post-upload MD5 checksum.
Q: How can I monitor my end users’ activity?
A: You can use Amazon CloudWatch to monitor your end users’ activity and use AWS CloudTrail to access a record of all S3 API operations invoked by your server to service your end users’ data requests. Visit the documentation on how to enable Amazon CloudWatch and AWS CloudTrail logging.
Q: How can I track amount of data uploaded and downloaded over the protocols?
A: You can use Amazon CloudWatch Metrics to monitor and track data uploaded and downloaded by your users over the chosen protocols. Visit the documentation to learn more on using Amazon CloudWatch metrics.
Q: How am I billed for use of the service?
A: You are billed on an hourly basis for each of the protocols enabled, from the time you create and configure your server endpoint, until the time you delete it. You are also billed based on the amount of data uploaded and downloaded over SFTP, FTPS, or FTP. Refer to the pricing page for more details
Q: Will my billing be different if I use the same server endpoint for multiple protocols or use different endpoints for each protocol?
A: No, you are billed on an hourly basis for each of the protocols you have enabled and for the amount of data transferred through each of the protocols, regardless of whether same endpoint is enabled for multiple protocols or you are using different endpoints for each of the protocols.
Q: I have stopped my server. Will I be billed while it is stopped?
A: Yes, stopping the server, by using the console, or by running the “stop-server” CLI command or the “StopServer” API command, does not impact billing. You are billed on an hourly basis from the time you create your server endpoint and configure access to it over one or more protocols until the time you delete it.
Q: How am I billed for using managed workflows?
A: There is no additional charge for using managed workflows. Depending on your workflow configuration, you are billed for use of Amazon S3, Amazon EFS, and AWS Lambda.
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