ACL Aliases

ACL alias functionality allows administrators to create reusable elements which can then be used when defining a destination in multiple ACL rules.

For example you can define aliases for commonly used ports (e.g. 22 for SSH) or for services within your infrustructure (e.g. 1.2.3.4:5432 for a particular PostgreSQL server).

Alias management

All the aliases defined in your systems are displayed in the second tab of the Access Control List page.

List of aliases

Similarly to ACL rules themselves, the list is split into two sections:

• Deployed Aliases – aliases that are active and can be used by ACL rules.

• Pending Changes – aliases that have been modified and have not yet been deployed.

To deploy pending changes use the Deploy pending changes button. It will deploy selected or all pending changes.

How to add and modify aliases

To create a new rule, use the Add new button on the list view.

You can edit an existing rule by using the context menu and selecting Edit in the list view.

In the ACL alias form you can specify alias name and type.

Below in the Destination section you can enter the same resource configuration as in the ACL rule Destination:

• IP addresses

• ports or port ranges

• protocols

Removing aliases

To remove an alias select the Delete alias option from the context menu.

Unlike with ACL rules, alias deletion is not tracked as a modification. You cannot delete an alias if it's being used by any rules and deleting unused aliases is immediate, not requiring changes to be deployed.

Using aliases in ACL rules

Aliases can be used to define an ACL rule destination by selecting them in the input within the Destination section:

Alias types

Aliases are divided into two distinct types to handle various use-cases:

• Destination alias – defines a complete ACL destination; it will be translated into a separate set of firewall rules.

• Component alias – defines a part of ACL destination; it will be merged with destination manually configured in a given ACL rule when generating firewall rules.

Examples

Let's start with an ACL rule that defines a following destination:

By itself this rule will allow specified users to access all ports and all protocols on the specified IP.

Component alias

Consider an SSH alias with a following definition:

When used in the previously created ACL rule, port 22 will be added to manual inputs defined in the rule itself.

In effect the rule will now grant access only to port 22 on 10.2.0.5, just like if we entered the port number in the rule's Manual Input section.

Destination alias

Now consider the following alias:

When used in the previously defined ACL rule it will have the following effects:

• the rule will still grant access to all ports and all protocols on 10.2.0.5

• it will also independently grant access to port 5432 in 10.2.0.38

In effect this is like if the rule has two separate destination inputs.

Underneath this is achieved by creating a separate set of firewall rules (one ALLOW and one DENY) for each destination alias.