AS2 Protocol Software | AS2 Server for File Transfers

What is AS2?

AS2 ( [Applicability Statement 2](/content/blog/what-is-as2 "What Is AS2? How the AS2 Protocol Works for Secure File Transfers"/index.html)) is a secure B2B file transfer protocol specification for transporting critical business data securely and reliably over the internet.

Upgraded from the original protocol (AS1) that was created in the 1990s, the AS2 protocol supports the encryption of messages (also known as AS2 messages) that are then exchanged with trading partners and vendors via HTTPS. These messages are built using the S/MIME format.

How Does the AS2 Protocol Work?

AS2 utilizes digital certificates and encryption standards to protect critical information while it’s in transit across systems, networks, and locations. AS2 digital document messages can be compressed, signed, encrypted, and sent over HTTPS using TLS.

Users can also request an MDN (known as Message Disposition Notification; also, sometimes referred to as "receipt") alert to verify that the message was received and decrypted successfully. Using signed receipts to compare the returned message checksum value creates a non-repudiation of receipt (NRR). An NRR gives the sender legal proof of unaltered delivery. This process gives organizations stronger evidence of delivery and helps reduce disputes with trading partners.

MDNs can be delivered in a variety of ways, including:

Synchronous MDN

This option allows the AS2 server connection to remain open until an MDN is received, or a timeout occurs.

Asynchronous MDN

This option allows the AS2 server connection to close immediately after the initial transmission is completed. When the server processes the AS2 message, the server will open a new connection and send the MDN.

Email MDN

This option allows the AS2 server to return an MDN to the sender via email.

AS2 Connections

The AS2 connection helps ease and secure the exchange of data between trading partners.

The messages sent via AS2 are sent over an HTTPS/TLS connection, making AS2 a very secure option for transferring files. In addition, with MDNs, AS2 helps ensure messages are delivered as intended. The AS2 protocol also helps meet compliance requirements as it uses signed receipts and compares them to the returned message checksum value for a non-repudiation of receipt (NRR). This is considered legal proof of delivery.

GoAnywhere supports AS2 connections through:

• Enforcing strong end-to-end encryption: GoAnywhere automatically encrypts messages and applies a digital signature via private key.
• Secure transmission: AS2 messages are sent securely over an SSL tunnel.
• Automated message processing: With GoAnywhere, once a file is received, [Advanced Workflows](/content/products/goanywhere-mft/workflows "Advanced Workflows"/index.html) can continue processing the message as determined by the admin.
• Error handling: MFT can ensure you know about any message fails before your recipient can auto-retry and send other alerts according to rules set by the admin.
• Receipt confirmation: MFT returns an MDN to confirm receipt of messages (whether successful, or if transmission failed)
• Centralized trading partner management: Users can configure, monitor, and manage AS2 partner profiles from the same interface.
• Compliance-ready logging: The system enables capturing AS2 transaction history, MDNs, timestamps, and processing details to support audits.
• Workflow integration: You can automatically route, translate, archive, or process AS2 messages after receipt.

Why Use AS2?

Using the AS2 protocol comes with unique advantages that ensure the streamlining of critical data exchange. These advantages include end-to-end encryption, strong authentication of senders and recipients through the use of digital signatures, and validation of file integrity with successful transfer confirmation.

AS2 is a secure industry standard protocol for sending sensitive data. Organizations using AS2 often choose it over other file transfer protocols (like FTP or SFTP) because of how it can support their compliance efforts by providing encryption, authentication, receipt confirmation, and auditable transaction records.

Benefits of AS2 & AS2 software

End-to-end encryption for sensitive files

Authenticating senders and recipients with digital signatures

Validation of file integrity with successful transfer confirmation

Ability to send/retrieve file transfers of any size or volume

Flexible support for synchronous or asynchronous MDN receipts

FTP vs AS2

Both FTP and AS2 are popular file transfer protocols and can serve organizations in distinct ways. Choosing which one is best for your business needs will depend on what level of security your data requires.

What is FTP?

File Transfer Protocol, or FTP, is the original standard network protocol used to transfer sensitive data between a client and a server on a network. It’s been around since the 1970s and is a common and simple method to transfer files for many organizations.

The FTP protocol works over a TCP/IP-based network using a client-server model and relies on two separate channels. The command (control) channel typically operates over TCP port 21, while the data channel uses different ports depending on whether the FTP connection is configured in active or passive mode. While FTP remains widely used for file transfers, it transmits data and credentials in plaintext, making it unsuitable for organizations that require secure data exchange and regulatory compliance.

Security Concerns of FTP

Authentication with FTP is via a username and password. However, access may also be possible without a login if the FTP server is configured to allow anonymous access. In addition, data is transmitted in plain text, which is susceptible to attacks and interception (this includes login credentials such as passwords and usernames).

For these reasons, using more secure protocols such as AS2, FTPS, and SFTP is recommended when transferring sensitive data and to protect authentication. FTP may still be useful within some low-risk legacy workflows, but it should not be used for sensitive or regulated data without additional safeguards.

How FTP Differs from AS2

Authentication:

• FTP sends user credentials such as usernames and passwords as plain text and does not encrypt files within the transfer window.
• AS2 authenticates with digital certificates for a higher level of security.

Encryption

• FTP operates over its own set of ports, supporting both active and passive modes
• AS2 leverages the security features of HTTP/HTTPS.

Message receipts/non-repudiation:

• AS2 allows users to request a Message Disposition Notification (MDN), or receipt which can alert the sender that the message was received and decrypted by the intended recipient. This can serve as legal proof that the file sent was received without alteration.
• FTP does not have MDN capabilities.

Digital Signatures:

• AS2 provides digital signatures to help ensure data integrity and authenticity.
• FTP does not use digital signatures.

Communication channels:

• FTP channels are unencrypted, leaving data open and vulnerable to interception.
• AS2 channels are encrypted to keep sensitive data protected.

Compliance:

• FTP lacks encryption functionality so cannot meet compliance requirements.
• AS2 uses encryption, which many regulatory bodies require. In addition, as AS2 can deliver acknowledgements and receipts, it helps satisfy auditing and tracking requirements.

Automation:

• GoAnywhere MFT can execute the same automation tasks for both FTP and AS2, as well as for other protocols. Automation can be used for tasks such as monitoring for new files then sending them automatically with the chosen protocol.

In general, while FTP may have been around for a long time and is a simple protocol to use, the more secure options of FTPS and SFTP as well as AS2 offer more protection to sensitive data.

Improve Your File Transfers with GoAnywhere's AS2 Protocol Solution

AS2 Client Software & Server

AS2 Client

The AS2 client software in GoAnywhere can automate the delivery of AS2 messages or send AS2 messages on a scheduled basis. It can automatically reconnect to the server if a connection breaks and retransmit the message. Both synchronous and asynchronous receipts can be logged to ensure AS2 messages were successfully processed by the trading partners. This means teams can scale outbound partner communications without relying on custom scripts or manual follow-up.

AS2 Server

The AS2 server software in GoAnywhere allows you to receive AS2 messages. Your trading partners can be authenticated using a combination of user credentials and X.509 certificates. This creates a controlled inbound exchange process for customers, suppliers, vendors, and trading partners. When a message is received, you can have a trigger automatically process the received files. For instance, GoAnywhere could move the AS2 documents to another area on the network or call an application to process these files.

Simplified Administration

GoAnywhere MFT provides a browser-based interface for configuring and monitoring AS2, AS3, and AS4 protocol file transfers and workflows. Each administrator can be assigned different permissions in GoAnywhere with their own custom dashboards.

• Configure AS2/AS3/AS4 file transfers and workflows using graphical wizards
• Set up AS2/AS3/AS4 trading partners quickly
• Easily create, import, and export X.509 certificates with AS2/AS3/AS4 certificate exchange
• Receive automatic status alerts on AS2/AS3/AS4 transfers
• View AS2/AS3/AS4 audit logs and analytical information
• Exchange sensitive digital documents with AS2/AS3/AS4 trading partners
• Assign role-based permissions to separate administrative responsibilities
• Monitor partner activity and transfer status from customizable dashboards

AS2 Client Software Features

Fully automates AS2 protocol transfers with an integrated scheduler

Provides graphical wizards to set up AS2 trading partners quickly

Encrypts messages and files using strong AES-256 bit encryption

Guarantees delivery with auto retry and auto-resume

Supports synchronous and asynchronous receipts

Can be scaled to handle unlimited AS2 partners

Generates detailed audit logs of all AS2 transfers

Securely transfers digital document files between businesses

AS2 Certificate

Drummond Certification

Drummond Certified is a label that the Drummond Group (a third-party certification body) gives to products and solutions that have proven their interoperability between AS2 vendors. The certification is extensive and helps ensure that the solution you use will allow you to successfully integrate with your AS2 trading partners. For enterprise teams, certification can mean a reduction in onboarding risk and improved confidence when connecting with new trading partners.

In order to pass the Drummond Certification process, any product attempting certification must conduct thousands of AS2 protocol test scenarios successfully in the Drummond Group's controlled, vendor-neutral environment. This process uses full matrix interoperability testing between AS2 vendor solutions to verify that important transactions maintain their security and integrity as they are transmitted over the Internet.

AS2 Drummond Certified™

GoAnywhere MFT is Drummond-certified for AS2 and meets the standards of Applicability Statement 2 (AS2) as a secure and widely adopted method for exchanging electronic documents with trading partners. This helps organizations meet partner requirements while reducing compatibility issues across AS2 ecosystems. Drummond Certification for AS2 helps ensure compliance and compatibility with other AS2 solutions through extensive interoperability testing.

Getting Started with AS2 File Transfers

Whether your trading partners require you to send files using AS2 or you’re looking for an industry standard protocol to transmit sensitive files that meet regulatory compliance, it’s easy to implement AS2 in your organization. You just need the right solution.

GoAnywhere MFT is a secure managed file transfer solution that simplifies, streamlines, audits, and automates your file transfers across a [variety of environments](/content/platforms "Platforms Basic Page "/index.html). It provides AS2 client and AS2 server software for small, medium, and enterprise-level organizations.

AS2 Tutorials

Learn how to transfer AS2 files with GoAnywhere MFT

Getting Started with File Transfer Services

Learn how to get started with file transfer services, such as FTP, FTPS, SFTP, HTTPS, AS2, and GoDrive.

How to Enable SSL for HTTPS/AS2 Server Connections

Learn the process to create an SSL certificate, have the certificate signed by a certificate authority, and assign the certificate to the HTTPS service.

Configuring the AS2 Client to Send AS2 Messages

The AS2 client is used to automate the transfer of data with an AS2 service. Learn how to configure the AS2 client in GoAnywhere MFT, create a Project to send an AS2 message, and then process the MDN receipt.

How to Configure the AS2 Service to Receive AS2 Transfers

Applicability Statement 2 (AS2) is a method used to securely send files over the internet. Learn how to configure AS2 in GoAnywhere MFT to enable encryption, signatures, compression and the use of receipts for delivery confirmation.

Configuring Web User Accounts to Receive AS2 Messages

After your AS2 Service is configured, you need to provision user accounts to access the service. Learn how to create and configure Web Users in GoAnywhere MFT that are used to transfer data using AS2.