Connect securely with your business

Wherever you are, with complete peace of mind Communications between human and technical teams are necessary, and security is essential. Connect your team members from anywhere in the world and with any device.

Aclass-Tier VPN works perfectly on:

Aclass creates secure networks between local devices, in the cloud, on desktop and mobile devices. Easily and securely connect to cloud resources, mobile devices, between desktop computers, and data centers anywhere and from any location. Access everything with Aclass. The Aclass VPN service runs on Windows, MacOS, Android, iOS, Linux, FreeBSD, and many popular NAS devices.
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Secure, simple, and fast VPN, just what you need.

Hire our widely compatible VPN service to connect all your devices, your home PC with your company’s PC, virtual machines in the cloud, local and remote servers, mobile devices with physical equipment, and everything as if the world were a big network at your disposal. Connect with your company’s remote desktops with complete confidence and security. Aclass can help you.


5.00 € / workstation / month + VAT


What includes?

Unlimited traffic
End-to-end encryption.
VPN with its own local network.
SO Windows, Linux, MacOS, Android, iOS


4.00 € / workstation / month + VAT


What  includes?

5 GB traffic/month.
End-to-end encryption.
VPN with its own local network.
SO Windows, Linux, MacOS, Android, iOS

Secure connection with your company

Features of this service This service includes the initial configuration, and necessary security updates for 12 months, of a secure access tunnel for a device/user based on a Virtual Private Network (VPN).

Think of your business with complete security

Setup and maintenance of Secure Connections Securely accessing your company’s desktops is no longer a problem with Aclass’s VPN access. Easy and fast.

Security Audit

The first step will be to analyze the state of your network, your equipment, and extract from this analysis those weak points that need to be improved so that access to your data is secure.

SSL Certificates

Secure and encrypted communication connection between employees’ devices and the company.

End-to-end encryption

Configuration of employee connections encrypted throughout their journey.

Access logging and blocking

Maintenance of a log of connections made to the company’s private network. Blocking of access to devices not expressly authorized by the company.

Mobile device access

Solutions for accessing your company’s network from mobile devices..

Configurations and training

This includes initial configuration, regular security updates, and necessary training for your staff to ensure the safe and proper use of access to your company’s network.

High performance

Aclass VPN utilizes point-to-point links, without intermediate points whenever possible, to minimize latency and maximize performance. The service typically consumes less than 64 MB of RAM.

Aclass-Tier secure point-to-point VPN service

Security in your business communications is essential today, don’t put it off any longer.
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Aclass-Tier VPN

combines VPN and SD-WAN capabilities, simplifying network management. Enjoy flexibility while avoiding the costly lock-in and management of hardware providers.
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We can set up Aclass-Tier VPN service in a matter of minutes with remote and automated deployment.
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Emulates layer 2 Ethernet with multipath, multicast, and bridging capabilities.
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Aclass VPN service’s zero-trust network solution provides scalable security with end-to-end 256-bit encryption.

Secure networks for teams of any type and size.

"IT Computer Equipment"

  • Simplify your network stack by unifying VPNs, VLANs, and SD-WANs with one solution
  • Integrate cloud devices on one interface
  • Easily provision and de-provision remote access for users, contractors, and partners


  • Easily build common backhaul networks that span multiple cloud providers
  • Save on performance, storage, and bandwidth by unifying on-premises applications with the cloud
  • Manage and debug from anywhere
  • Secure corporate network overlay and failover switching layer

Product Companies

  • Aclass VPN service provides network control and P2P functionality
  • Use Aclass VPN service to create products that run on your own decentralized networks
  • Create a secure P2P network with 5G capability for any IoT (Internet of Things) device that can operate with just 64 MB of RAM

Individual Users

  • Access your desktop, NAS, and other devices from anywhere
  • Conveniently share files, data, and play on LAN
  • Grant access to personal systems to desired users

The benefits of implementing secure communications within your company

Secure communications are those that ensure the confidentiality, integrity, and availability of the information transmitted between different parties. These communications are essential to protect sensitive data of your company, such as personal data of your clients, trade secrets, business strategies, or financial transactions.
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Strengthen your company with data protection.

Improve the reputation and trust of your company among your customers, suppliers, collaborators, and employees by demonstrating that you care about the security of their data and comply with current regulations regarding data protection.
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Avoid costly IT risks.

Reduce the risk of suffering from computer attacks, such as phishing, malware, ransomware, or identity theft, which can compromise your company’s information and cause serious financial losses or reputational damage.
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Save time with updated systems.

Increase the productivity and efficiency of your company by avoiding interruptions or delays in communications caused by security issues or the use of outdated or incompatible systems.
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Optimize your teamwork.

Facilitate teamwork and collaboration among employees in your company by allowing them to communicate quickly, easily, and securely from anywhere and any device using tools such as email, instant messaging, video conferencing, or cloud storage.
To implement secure communications within your company, it is necessary to have an adequate infrastructure, which includes elements such as a secure server, a virtual private network (VPN), a firewall, antivirus, data encryption, or a digital certificate. Additionally, it is important to train employees on good security practices and establish clear and coherent policies on the use of communications in the workplace.
Secure communications are a profitable investment for your company, which will allow you to improve your competitiveness and growth in the market. If you want more information on how to implement secure communications within your company, do not hesitate to contact us. We will be happy to advise you and offer you the best solutions tailored to your needs. The extraordinary technical team of Aclass will analyze and offer you the best solution to ensure that your communications are completely secure.

Your security is our goal

Let us know the needs of your company, your team, and we will provide you with the best option.

Want to know more about Aclass-Tier VPN?

Notes on the protocol design of Aclass-Tier’s point-to-point VPN service.


Aclass Tier is an intelligent Ethernet switch service for a variety of solutions. It is a distributed network hypervisor built on a cryptographically secure peer-to-peer global network. It provides advanced virtualization and network management capabilities akin to an enterprise SDN switch, but across local and wide area networks and connecting nearly any type of application or device. This manual describes the design and operation of Aclass Tier and its associated services, applications, and libraries. It is intended for IT professionals, network administrators, information security experts, and developers. The first section (2) of this guide explains the high-level design and operation of Aclass Tier and is written for those with at least intermediate knowledge of topics like TCP/IP and Ethernet networks. It is not required reading for most users, but understanding how things work in detail helps to clarify everything else and greatly aids in troubleshooting if something goes wrong. The remaining sections deal more specifically with deployment and management.
Overview of the network hypervisor

The Aclass Tier network hypervisor is a standalone network virtualization engine that implements an Ethernet virtualization layer similar to VXLAN over a globally encrypted peer-to-peer network.

The protocol used by Aclass Tier is original, although it has similarities to VXLAN and IPSec. It has two conceptually separate but tightly coupled layers in the sense of the OSI model: VL1 and VL2. VL1 is the underlying peer-to-peer transport layer, the “virtual cable,” while VL2 is an emulated Ethernet layer that provides operating systems and applications with a familiar communication medium.

VL1: The Aclass Tier Peer to Peer Network
A global data center requires a global cable rack. In conventional networks, L1 (OSI layer 1) refers to the actual CAT5/CAT6 cables or wireless radio channels that transport data, and the physical transceiver chips that modulate and demodulate them. VL1 is a peer-to-peer network that does the same thing using encryption, authentication, and a bunch of network tricks to dynamically create virtual cables as needed.
Network topology and peer discovery
VL1 is designed to be zero-configuration. A user can start a new Aclass Tier node without having to write configuration files or provide IP addresses of other nodes. It is also designed to be fast. Any two devices in the world should be able to locate each other and communicate almost instantly. To achieve this, VL1 is organized as a DNS. At the base of the network, there is a collection of root servers that are always present and whose function is similar to that of DNS root name servers. The root servers run the same software as normal endpoints, but reside in stable and fast locations in the network and are designated as such by a world definition. World definitions come in two types: the planet and one or more moons. The protocol includes a secure mechanism for updating world definitions in-band if the IP addresses of root servers or Aclass Tier addresses change. Currently, Aclass uses external servers and provides its own servers for secure VPN network intercommunication. There are twelve root servers organized into two clusters of six members distributed across the major continents and multiple network providers. Almost everyone has one within 100 ms of network latency from their location. A node can “orbit” any number of moons. A moon is just a convenient way to add user-defined root servers to the pool. Users can create moons to reduce dependency on Aclass Tier infrastructure or to locate root servers closer for better performance. For local SDN use, a cluster of root servers can be located within a building or data center so that Aclass Tier can continue to function normally if Internet connectivity is lost. Nodes start without direct links to each other, only upwards to the roots (planet and moons). Each peer in VL1 has a unique 40-bit global address (10 hexadecimal digits), but unlike IP addresses, these are opaque cryptographic identifiers that do not encode any routing information. To communicate, peers first send packets “upward” the tree and, as they traverse the network, opportunistically create direct links along the way. The tree constantly tries to “collapse” to optimize itself to the traffic pattern it carries.
The configuration of a peer-to-peer connection is as follows

1. A wants to send a packet to B, but as it has no direct route, it sends it upstream to R (a root).
2. If R has a direct link to B, it forwards the packet there. If not, it sends the packet upstream until it reaches planetary roots. Planetary roots know all the nodes, so the packet will eventually reach B if B is connected.
3. R also sends a message called rendezvous to A that contains clues about how it might reach B. Meanwhile, the root forwarding the packet to B sends rendezvous informing B of how it might reach A.
4. A and B receive their rendezvous messages and try to send test messages to each other, possibly succeeding in punching holes in any NAT or stateful firewall that is in the way. If this works, a direct link is established, and packets no longer need to take the scenic route.

Since the roots forward the packets, A and B can communicate instantly. A and B then attempt to establish a peer-to-peer direct connection. If successful, a faster and lower latency link is achieved. We call this link provision-triggered transport, as it is the packet forwarding itself that triggers the peer-to-peer network to attempt the direct connection.

VL1 never gives up. If a direct route cannot be established, communication can continue through relay (slower). Attempts to establish a direct connection continue forever periodically. VL1 also has other features to establish direct connectivity, including LAN peer discovery, prediction of ports to traverse symmetric IPv4 NATs, and explicit port mapping using uPnP and/or NAT-PMP if available on the local physical LAN.


Each node is uniquely identified in VL1 by a 40-bit (10 hexadecimal digits) Aclass Tier address, which is calculated from the public part of a public/private key pair. The address, public key, and private key of a node form its identity.

In devices running Aclass Tier, the node’s identity is stored in identity.public and identity.secret in the main service directory.

When Aclass Tier is first started, it generates a new identity and attempts to announce it to the network. In the highly unlikely event that the unique 40-bit address of the identity is already taken, it discards it and generates another.

Identities are claimed on a first-come, first-served basis and currently expire after 60 days of inactivity. If a long inactive device returns, it can reclaim its identity unless its address has been taken in the meantime (again, highly unlikely).

The address derivation algorithm used to calculate addresses from public keys imposes a computational cost barrier against the intentional generation of a collision. Currently, it would take approximately 10,000 years of CPU time to do so (assuming, for example, an Intel 3ghz core). This is expensive but not impossible, but it is only the first line of defense. After generating a collision, an attacker would have to compromise all upstream nodes, network controllers, and anything else that has recently communicated with the target node and replace their cached identities.

Aclass Tier addresses are, once announced and claimed, a very secure method of unique identification.

When a node attempts to send a message to another node whose identity is not cached, it sends a whois query to a root. The roots provide an authorized identity cache.


If you don’t know much about cryptography, you can skip this section. TL;DR: the packets are end-to-end encrypted and cannot be read by the roots or anyone else, and we use modern 256-bit cryptography in the forms recommended by professional cryptographers who created it.

Asymmetric public key encryption is Curve25519/Ed25519, a variant of 256-bit elliptic curve.

Each VL1 packet is end-to-end encrypted using (starting from the current version) Salsa20 256-bit and authenticated using the message authentication algorithm (MAC) Poly1305. MAC is calculated after encryption (encrypt-then-MAC) and the encryption/MAC composition used is identical to the NaCl reference implementation.

Currently, we do not implement forward secrecy or other cryptographic features with state in VL1. We do not do so for the sake of simplicity, reliability, and code footprint, and because frequent state changes make features such as batching and error switching much harder to implement.

We may implement forward secrecy in the future. For those who want this level of security today, we recommend using other cryptographic protocols such as SSL or SSH over Aclass Tier. These protocols typically implement forward secrecy, but their use over Aclass Tier also provides the secondary benefit of defense in depth. Most cryptography is not compromised by a failure in encryption, but by errors in implementation. If you use two secure transports, the chances of a critical failure being discovered in both at the same time are very low. The CPU overhead of double encryption is not significant for most workloads.

Trust paths for a fast local SDN

To support the use of Aclass Tier as a high-performance SDN/NFV protocol over physically secure networks, the protocol supports a feature called trust paths. It is possible to configure all devices linked to a particular Aclass Tier network to bypass encryption and authentication of traffic through a designated physical path. This can significantly reduce CPU usage in high-traffic situations, but at the cost of virtually all transport security.

Trust paths do not prevent communication with devices from other locations, as traffic through other paths will still be encrypted and authenticated normally.

We do not recommend using this feature unless you really need the performance and know what you are doing. We also recommend thinking carefully before disabling transport security on a private cloud network. Larger cloud providers such as Amazon and Azure tend to provide good network segregation, but many cheaper providers offer private networks that are “party lines” and are not much more secure than the open Internet.

Multipath allows for the simultaneous (or conditional) aggregation of multiple physical links into one link to increase overall performance, load balancing, redundancy, and fault tolerance. A set of standard link policies is available for immediate use without the need for configuration. These policies are inspired by those offered by the Linux kernel. A link policy can be easily used without specifying any additional parameters.
VL2: The Ethernet Virtualization Layer
VL2 is a network virtualization protocol similar to VXLAN with SDN management features. It implements secure VLAN boundaries, multicast, rules, capability-based security, and certificate-based access control. VL2 is built on top of VL1 and transported through it, inheriting VL1’s endpoint encryption and authentication, and can use VL1’s asymmetric keys to sign and verify credentials. VL1 also allows us to implement VL2 without worrying about the underlying physical network topology. Connectivity and routing efficiency issues are VL1’s concerns. It’s important to understand that there is no relationship between VL2 virtual networks and VL1 routes. Like VLAN multiplexing on a wired LAN, two nodes sharing multiple network memberships in common will only have one VL1 route (virtual cable) between them.
Identifiers and Network Controllers

Each VL2 network (VLAN) is identified by a 64-bit (16 hexadecimal digits) Aclass Tier network ID, which contains the 40-bit Aclass Tier address of the network controller and a 24-bit number identifying the network on the controller.

Network ID: 8056c2e21c123456
| |
| Network number on the controller
Aclass Tier address of the controller

When a node joins a network or requests a network configuration update, it sends a network configuration query message (via VL1) to the network controller. The controller can then use the node’s VL1 address to look it up on the network and send it the appropriate certificates, credentials, and configuration information. From the perspective of VL2 virtual networks, Aclass Tier VL1 addresses can be thought of as port numbers on a huge global-scale virtual switch.

A common misunderstanding is to confuse network controllers with root servers (planet and moons). Root servers are connection facilitators that operate at the VL1 level. Network controllers are configuration managers and certification authorities that belong to VL2. Generally, root servers do not join or control virtual networks, and network controllers are not root servers, although it is possible for a node to do both.

Security considerations for controllers

Network controllers serve as certification authorities for Aclass Tier virtual networks. As such, their identity.secret files must be closely monitored and securely backed up. Compromising a controller’s secret key would allow an attacker to issue fraudulent network configurations or admit unauthorized members, while losing the secret key results in the loss of the ability to control the network in any way or issue configuration updates, effectively rendering the network unusable.

It is important that the system clocks of controllers are relatively accurate (within 30 to 60 seconds) and protected against remote manipulation. Many cloud providers provide secure time sources, either directly through the hypervisor or via NTP servers within their networks.

Certificates and other credentials
All credentials issued by network controllers to member nodes of a given network are signed by the controller’s secret key so that all network members can verify them. The credentials have date and time fields filled in by the controller, allowing for relative comparison without relying on the local node’s system clock. Credentials are only issued to their owners, and nodes wishing to communicate with other nodes in the network send them peer-to-peer. This allows networks to grow to enormous sizes without requiring nodes to cache a large number of credentials or constantly query the controller.
Multicast modes, ARP, NDP, and special addressing

Aclass Tier networks support multicast through a simple publish/subscribe system.

When a node wants to receive multicasts for a specific multicast group, it announces its membership to that group to other members of the network it communicates with and to the network controller. When a node wants to send a multicast, it checks its cache of recent announcements and periodically requests additional announcements.

Multicast (Ethernet ff:ff:ff:ff:ff:ff) is treated as a multicast group to which all members subscribe. It can be disabled at the network level to reduce traffic if not needed. IPv4 ARP receives special treatment (see below) and will continue to work if normal broadcast is disabled.

Multicasts are propagated using simple sender-side replication. This places all outgoing multicast bandwidth load on the sender and minimizes multicast latency. Network configurations contain a network-wide multicast limit configurable on the network controller. This specifies the maximum number of other nodes any node will send a multicast to. If the number of known recipients in a particular multicast group exceeds the multicast limit, the sender chooses a random subset.

There is no global limit on multicast recipients, but setting a very high multicast limit in very large networks could cause significant bandwidth overload.

Special treatment of IPv4 ARP broadcasts

IPv4 ARP is based on simple Ethernet broadcast and scales poorly in large or distributed networks. To improve ARP scalability, Aclass Tier generates a unique multicast group for each detected IPv4 address in its system and then transparently intercepts ARP queries and sends them only to the correct group. This converts ARP into a narrowcast or multicast protocol (like IPv6 NDP) and allows IPv4 ARP to function reliably in wide area networks without excessive bandwidth consumption. A similar strategy is applied under the hood of a number of enterprise switches and WiFi routers designed for deployment in extremely large LANs. This ARP emulation mode is transparent to the operating system and application layers, but means that packet trackers will not see all ARP queries in a virtual network in the way they normally do in smaller wired LANs.

Modes of IPv6 addressing without multicast
IPv6 uses a protocol called NDP instead of ARP. It is similar in function and design, but uses narrow multicast instead of broadcast for superior scalability in large networks. However, this protocol still imposes the latency of an additional multicast lookup each time a new address is contacted. This can add hundreds of milliseconds in a wide area network, or more if latencies associated with pub/sub recipient lookup are significant. IPv6 addresses are large enough to easily encode Aclass Tier addresses. For faster operation and better scaling, we have implemented several special IPv6 addressing modes that allow the local node to emulate NDP. These are the Aclass Tier IPv6 address assignment schemes rfc4193 and 6plane. If these addressing schemes are enabled on a network, nodes locally intercept outgoing NDP queries for matching addresses and generate false NDP responses locally. Both modes drastically reduce the latency of the initial connection between members of the network. 6plane further exploits NDP emulation to transparently assign a complete /80 IPv6 prefix to each node without requiring any additional entries in the routing table. This is intended for virtual machine and container hosts that wish to self-assign IPv6 addresses to guests and is very useful in microservices architecture backplane networks. Finally, NDP emulation offers a security advantage. Aclass Tier addresses are cryptographically authenticated, and since Ethernet MAC addresses on networks are computed from Aclass Tier addresses, they are also secure. Therefore, the IPv6 addressing modes emulated by NDP are not vulnerable to NDP response spoofing. Normal IPv6 addresses not emulated by NDP (including link-local addresses) can coexist with NDP-emulated addressing schemes. Any NDP queries that do not match NDP-emulated addresses are sent via normal multicast.
Ethernet Bridging

Aclass Tier emulates a true Ethernet switch. This includes the ability to bridge L2 other Ethernet networks (wired LAN, WiFi, virtual backplanes, etc.) to virtual networks using conventional Ethernet bridges.

To act as a bridge, a member of the network must be designated as such by the controller. This is for security reasons, as normal network members are not allowed to send traffic from any source other than their MAC address. Designated bridges also receive special treatment by the multicast algorithm, which aggressively and directly requests their subscriptions to groups and replicates all broadcast traffic and ARP requests to them. As a result, bridge nodes experience a slightly higher multicast bandwidth overload.

Bridging has been extensively tested on Linux using the native Linux kernel bridge, which cleanly handles network MTU mismatches. There are third-party reports on bridging operation on other platforms. The details of bridge configuration, including how to selectively block traffic such as DHCP that may not be desired over the bridge, are beyond the scope of this manual.

Public networks

It is possible to deactivate access control in an Aclass Tier network. Members of a public network do not check membership certificates, and new members of a public network are automatically marked as authorized by their host controller. It is not possible to deauthorize a member of a public network.

On the other hand, rules are enforced, so it is possible to implement a special-purpose public network that only allows access to a few things or only allows a restricted subset of traffic.

Public networks are useful for testing and “party lines” among peers for games, chat, and other applications. Participants in public networks are advised to pay special attention to security. If you join a public network, be careful not to expose vulnerable services or accidentally share private files through open network shares or HTTP servers. Make sure your operating system, applications, and services are fully updated.

Ad-Hoc Networks
A special type of public network called an ad-hoc network can be accessed by joining a network ID with the format: ffSSSSEEEE000000 | | | | | | | End of port range (hex) | | Start of port range (hex) Reserved Aclass Tier address prefix indicating a controllerless network Ad-hoc networks are public networks (without access control) that do not have a network controller. Instead, their configuration and other credentials are generated locally. Ad-hoc networks only allow IPv6 UDP and TCP unicast traffic (no multicast or broadcast) using emulated IPv6 NDP addresses in 6plane format. Additionally, an ad-hoc network ID encodes a range of IP ports. UDP packets and TCP SYN (open connection) packets are only allowed to destination ports within the encoded range. For example, ff00160016000000 is an ad-hoc network that only allows SSH, while ff0000ffff000000 is an ad-hoc network that allows any UDP or TCP port. Note that these networks are public and anyone in the world can join them. Care should be taken to avoid exposing vulnerable services or sharing unwanted files or other resources.
Quality of Service (QoS)

In a future version (not yet implemented in version 1.4.2), Aclass Tier will support new traffic prioritization rules based on link measurement functions. There will be nine categories available for traffic classification: [0, 1, 2, 3, (4), 5, 6, 7, 8], each with a geometrically increasing priority, with block 4 being the default in the absence of a classification rule for a specific traffic type.

For example, let’s say you want to prioritize your VoIP traffic over standard web traffic:

priority 6
ip protocol udp
and dport 5060-5065
and sport 5060-5065

priority 3
ip protocol tcp
and dport 80
and sport 80

This would place VoIP traffic on ports 5060 to 5065 at a higher priority 6 than standard web traffic on port 80 in block 3.


Now include your company’s communication protection. At Aclass, we offer high-quality VPN services to protect your online privacy and security. Our flexible VPN packages focus on providing a secure and encrypted Internet connection, regardless of your location or device. By working with us as your VPN service provider, you can choose which VPN plan best suits your needs and budget, from basic VPN plans to advanced enterprise solutions. Our comprehensive VPN services allow you to browse the web securely and access geographically restricted content, and are designed to ensure your online privacy and anonymity. Below, you can learn about our affordable VPN packages and discover how we can help you protect your online privacy.

Contact Aclass

Customer service is our top priority. Aclass is always close to you. If you want to visit us, we will be happy to welcome you to our headquarters:

Where are we located?

Aclass Internet, S.L.
Alfonso XII, 62 – 2º Piso, 28014 Madrid Spain

Phone number

Aclass internet y comunicaciones