As a follow up to my earlier post Access Gateway Licensing Demystified, I want to add some Licensing details around HA – High Availability. I have received ample questions around how licensing works with HA, and I hope to be able to answer those here.

Once again, note that the Access Gateway discussed in this blog is the Access Gateway based on NetScaler, which is popularly referred to as Access Gateway Enterprise. Citrix has recently announced End of Life for all non-NetScaler based Access Gateway platforms, which then makes Enterprise edition, the de-facto Access Gateway.

High Availability

HA on an Access Gateway appliance is essentially an Active/Passive Failover deployment. In this deployment, one Access Gateway accepts and manages connections, while a second Access Gateway monitors the first appliance. If the first Access Gateway stops accepting connections for any reason, the second Access Gateway takes over and begins actively accepting connections. This configuration prevents downtime and ensures that the services provided by Access Gateway remain available, even if one Access Gateway is not working.

For details on how to configure HA on your Access Gateway appliances, more details are available here – EDocs

HA Licensing

Licensing on Access Gateway is always tied to the host name of the appliance. To set up 2 appliances in a HA configuration, one of the main requirements is to assign the same host name to both the appliances. Once this is done, you can go to your ‘MyCitrix’ account and allocate the licenses (both platform and universal, if purchased) to this host name. These can then be downloaded and applied to the Access Gateway appliances. Note that applying the same license on both the appliances is in agreement with the Citrix EULA (End User Licensing Agreement). Citrix EULA allows the same license to be installed on an unlimited number of appliances, as long as the total number of concurrent connections across all appliances in the setup does not exceed the total number of licenses purchased. This works for our HA pair since at any given point of time, only one of the appliances is going to be active.

Note: If you need details around how Platform Licenses and Universal Licenses work on Access Gateway, please refer to my earlier post – Access Gateway Licensing Demystified

Scenario

Lets say you purchases 100 CloudGateway Enterprise licenses, to provide secure mail and secure browser capabilities for your mobile sales force. To provide remote access, you also purchase two Access Gateway VPXs and configures them to work in HA.  With these purchases, you receives the following licenses:

  1. 100 CloudGateway Enterprise licenses
  2. 100 Access Gateway Universal licenses
  3. 2 AG VPX Platform licenses

As a part of the HA configuration, lets say the hostname for both the appliances is configured as ‘ag.abc.com’. Next step is for the customer to go to his MyCitrix account, allocate the 100 Universal Licenses and 1 Platform license for ‘ag.abc.com’. These are then downloaded and applied on both the Access Gateway VPXs. Your HA is good to go.