In most environments the Netbios protocol is used to resolve names and it is the primary cause of the delay in the Application Enumeration. The issue can be isolated by analyzing the Network Monitor Traces in which each
NetBios request takes between 1.82 and up to 2.23 seconds in worst cases to complete, and there are a lot of NetBios requests submitted, especially when a user with access to over 4000 Resources logon to Storefront.
So what can we do to speed up the enumeration process?

1. The problem is partly causes by the XenServer PV Ethernet Adaptor Advanced Offload Properties.

When you install the XenServer virtualization drivers on your Storefront, XenApp or XenDesktop servers, You should be able to see the following five Offload adaptor settings on your network configuration (depends on XS version):

  • IPv4 Checksum Offload
  • Large Receive Offload (IPv4)
  • Large Send Offload Version 2 (IPv4)
  • TCP Checksum Offload (IPv4)
  • UDP Checksum Offload (IPv4)


As a workaround, you can just Disable all the five properties without any restart required. Make these changes on your XenApp, XenDesktop, Citrix Secure Gateway, Web Interface and Storefront servers.

2. We’re not done yet. The second part of this long solution is to disable NetBios over TCP/IP on the XenApp, XenDesktop, Web Interface and Storefront servers. To do so, complete one of following procedure
for the relevant environment:Disable NetBios

  • Click Start, and then click Control Panel.
  • Under Network and Internet, click View network status and tasks.
  • Click Change adapter settings.
  • Right-click Local Area Connection > Properties.
  • In the This connection uses the following items list, double-click Internet Protocol Version 4 (TCP/IPv4), click Advanced > WINS tab.’
  • Click Disable NetBios over TCP/IP, and then click OK twice.

3. After restarting IIS, or rebooting the Web Interface / Storefront server, it takes up to one minute to get the Welcome / Logon page for the first user.

This issue is caused by a CRL check sent to Verisign. If the Web Interface / Storefront server cannot access the internet, the CRL check fails and times out.

  • Check in IIS for the version that is in use with the Web Interface / Storefront site.
    Modify Aspnet.config  in the following directory
    C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727 (If Web Interface / Storefront uses .Net framework v2.0.50727)
  • Add the following lines to your ASPNET.CONFIG or APP.CONFIG file: <?xml version=”1.0″ encoding=”utf-8″?> <configuration>     <runtime>         <generatePublisherEvidence enabled=”false”/>     </runtime> </configuration>

4. To be sure that the DNS is the protocol being used to resolve the name of the XenApp / XenDesktop on the Web Interface / Storefront, use the following procedure:

  • In the Storefront Console, at Manage Delivery Controllers, specify the fully qualified domain name (FQDN) of the STA acting Machines “brokers” instead of the Netbios or the IP address.
  • And create an entry for each STA (broker) into the host file of the Storefront / Webinterface server.
  • In case you are loadbalancing your “brokers” via Netscaler, make sure you specify the NetBios name instead of the FQDN in the content Switch pilicy expression at the Netscaler:
    And of course do not forget to update the host file of the Storefront / Webinterface server using the IP of the content switch vserver your are using.