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Policy

Policies allow Administrators to centrally define which Managed systems in their account should be connected to one another and under what conditions.

Production use: Changes to policies take effect immediately and Enclave will quickly build direct connectivity between enrolled systems impacted by each Policy.

Access control

Each Policy is composed of Tags which are assigned to one of two roles: a Sender role and a Receiver role. Traditional firewalls are often configured to permit outbound traffic but block all inbound or unsolicited traffic. In much the same way, Enclave will allow systems in the Sender role to originate traffic to systems in the Receiver role but not the reverse.

Systems are grouped together under common Tags and Tags are attached to Policies. As an example, consider the following policy:

Policy Name Sender Tags Receiver Tags
Kubernetes access developers
contractors
kubernetes-pods

Any system which is a member of either the developers or contractors Tags will be connected to any system in the kubernetes-pods Tag, but systems in the developers Tag will not be connected to other developers or contractors by this Policy.

Systems in the kubernetes-pods Tag will be unable to initiate outbound connections to developers or contractors systems, as the Receiver role prohibits unsolicited traffic and only allows responses to traffic which originated from a system with the Sender role.

Unlike the public Internet, without an Enclave connection in place between two peers, no traffic can be send across an Enclave link; this means access controls can be exclusively Receiver defined. There is no way to apply sender-side restrictions to an Enclave peer to prohibit what can or can't be sent to other peers, all access controls are applied by the Receiver and govern what each system is willing to accept.

Depending on how Administrators arrange Tags in each a Policy they may create either partially connected or fully connected mesh topologies.

Access Control Rules

Once you have indicated which systems should be communicating, using tags, you then want to define what traffic is allowed to move between Sender and Receiver. You can control this per-policy with Access Control Rules.

Access Control Rules allow you to define which protocol and port(s) you want to allow into systems on the Receiver side of the Policy.

Applying Access Controls at the Receiver side of a policy makes the entire system much easier to reason about. You can set up traffic rules in a similar way to setting up firewall rules to allow access to a service. The way rules are applied should feel pretty intuitive, but fundamentally:

  1. If you don't specify any rules on your policy, no traffic will flow (default deny)
  2. Each ACL rule only applies to connections between the senders and receivers of the policy where it was defined.
  3. Different rules on different policies affecting the same systems are combined, but still respecting rule #2.

When you create a new policy, by default we add a rule that allows All Traffic to flow between Sender and Receiver. Remove this rule to restrict the set of traffic you want to allow.

Naming

The Enclave access control model is defined by the Receiver role of each Policy, so Policy names should normally reflect the resource accessed and consumer(s) in an X for Y pattern.

For example if a Policy defines access to a GitLab server for Developers, naming the policy GitLab for Developers provides a clear and concise description.

Separate policies may grant access to the same resource or set of resources. For example, one Policy may grant Developers to access Database Servers during working hours and a separate policy may grant the Site Reliability Engineering (SRE) team 24/7 access to the same Database Servers.

  • Database Servers for Developers
  • Database Servers for SRE

Topology

Connectivity is established between the systems with membership in Tags attached on the Sender and Receiver side, but never between systems on the same side.

Partially connected mesh

In a partially connected mesh, only specific systems connect to one another across the policy. This assumes that no systems belong to Tags on multiple sides of the Policy.

Policy Name Sender Tags Receiver Tags
Server access for Workstations workstations servers

Fully connected mesh

Full mesh connectivity arises when multiple systems are members of Tags on both sides of a Policy, all affected systems are connected to one another. In the following example a Policy defines connectivity between systems tagged with the servers Tag.

Policy Name Sender Tags Receiver Tags
Servers full mesh servers servers

Fully connected mesh networks may create large numbers of connections between participating systems. The number of connections in a fully connected mesh is equal to N∗(N−1)/2 (i.e. number of systems times the number of systems minus 1, divided by 2).

A fully connected mesh of 16 systems will create 120 connections, where as a mesh twice the size with 32 participants will create 496 connections. You should consider the capabilities of your underlying network infrastructure when deploying a fully connected mesh as some stateful network appliances impose limits on the maximum number of connections they can track or support.