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Secure user sessions using TLS
As of Version 7.16, the Linux VDA supports TLS encryption for secure user sessions. TLS encryption is disabled by default.
Enable TLS encryption
To enable TLS encryption for secure user sessions, obtain certificates and enable TLS encryption on both the Linux VDA and the Delivery Controller (the Controller).
Obtain certificates
Obtain server certificates in PEM format and root certificates in CRT format from a trusted Certificate Authority (CA). A server certificate contains the following sections:
- Certificate
- Unencrypted private key
- Intermediate certificates (optional)
An example of a server certificate:
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
Enable TLS encryption
Enable TLS encryption on the Linux VDA
On the Linux VDA, use the enable_vdassl.sh tool to enable (or disable) TLS encryption. The tool is located in the /opt/Citrix/VDA/sbin directory. For information about the options available in the tool, run the /opt/Citrix/VDA/sbin/enable_vdassl.sh -help command.
Tip: A server certificate must be installed on each Linux VDA server and root certificates must be installed on each Linux VDA server and client.
Enable TLS encryption on the Controller
Note:
You can enable TLS encryption only for entire delivery groups. You cannot enable TLS encryption for specific applications.
In a PowerShell window on the Controller, run the following commands in sequence to enable TLS encryption for the target delivery group.
- Asnp citrix.*
- Get-BrokerAccessPolicyRule –DesktopGroupName ‘GROUPNAME’ | Set-BrokerAccessPolicyRule –HdxSslEnabled $true
Note:
To ensure that only VDA FQDNs are contained in an ICA session file, you can also run the
Set-BrokerSite –DnsResolutionEnabled $truecommand. The command enables DNS resolution. If you disable DNS resolution, an ICA session file discloses VDA IP addresses and provides FQDNs only for the TLS-related items such as SSLProxyHost and UDPDTLSPort.
To disable TLS encryption on the Controller, run the following commands in sequence:
Asnp citrix.*Get-BrokerAccessPolicyRule –DesktopGroupName ‘GROUPNAME’ | Set-BrokerAccessPolicyRule –HdxSslEnabled $falseSet-BrokerSite –DnsResolutionEnabled $false
Troubleshooting
The following “Can’t assign requested address” error might occur in Citrix Workspace app for Windows when you try to access a published desktop session:
As a workaround, add an entry to the hosts file, which is similar to:
10.108.13.180 rhvm72work.citrixlab.local
Where
- 10.108.13.180 is the IP address of the Linux VDA.
- rhvm72work.citrixlab.local is the FQDN of the Linux VDA.
On Windows machines, the hosts file typically locates at C:\Windows\System32\drivers\etc\hosts.