To make this work without the need of configuring your DNS servers, you need to configure your GSLB NetScaler to use the TCP protocol.
Let’s suppose that your GSLB is already up and running, and that the following is already in place:
1. DNS zone
2. ADNS Server.
3. Next step will be configuring a ADNS_TCP service to make the GSLB DNS listen to TCP requests. You could assign the same IP you used for the ADNS server.

Now we need to configure a SRV Records for a Service and assign it to a target. The target is just a DNS record binded to a GSLB virtual server pointing to a access gateway virtual server.
The SRV record provides information about the services available on the NetScaler appliance. An SRV record contains the following information: name of the service and the protocol, domain name, TTL, DNS class, priority of the target, weight of records with the same priority, port of the service, and host name of the service. The NetScaler chooses the SRV record that has the lowest priority setting first. If a service has multiple SRV records with the same priority, clients use the weight field to determine which host to use.

To add an SRV record (Email-Based Account Discovery) by using the NetScaler command line. At the NetScaler command prompt, type the following command to add an SRV record and verify the configuration:
add dns srvRec _citrixreceiver._tcp.”domainname” -priority 1 -weight 1 -port 443

Example: Suppose that your domain name looks like this: “”, then the code will be:
add dns srvRec -priority 1 -weight 1 -port 443

Now, you should be able to configure your receiver by entering: