Citrix Session Slowness

Recently i faced a very strange issues regarding Citrix sessions. Users are complaining that they are getting very slow response whenever they open Citrix website from web interface.  After initial analysis it has been noted that there is almost 3 minutes delay in displaying web interface page after successful authentication. After further analysis and also getting help from Citrix support it has been found that there is no reverse DNS zone entry in DNS servers for Citrix severs subnet. Because the environment is new and the application which is facing problem is the first application, so the issue has not been identified before. After entering Citrix Servers Subnet in reverse lookup zone the performance is dramatically increased and the web interface page is now opening in seconds.

As per Citrix support “You have a DNS resolution issue on the WI server just when the client machine send the login information to WI, the WI box does a DNS query to 10.201.X.X which fails for X.X.201.10.in-addr.arpa. after several DNS queries exchanges with different DNS servers, a NetBios call succeed to return 10.201.X.X and then the Citrix XML communication starts.”  (They have also told us to disable SNMP which was not enabled because we are not using it)

Following tests has been conducted in order to narrow down this issues;

1. Network trace on the workstation.

2. Network trace on the XML broker server.

3. Network trace on the web interface server.

4. CDF trace on below modules on XML broker server:

IMA_Subsystems_ComSrv

IMA_Subsystems_MfServer

IMA_Sals_MfServer

MF_XMLRelay_Admin

MF_XMLRelay_Wpnbr

5. CDF trace on below modules on Zone Data collector server :

IMA_Subsystems_UserWin

IMA_Subsystems_ComApp

IMA_Subsystems_ComSrv

IMA_Subsystems_MfServer

MF_DLL_Ccticket

IMA_Subsystems_MfApp

IMA_Subsystems_User

IMA_Sals_MfServer

IMA_Sals_User

IMA_Sals_UserWin

IMA_RunTime_DynamicStore

 

For CDF tracing CDF Control Application is required which can be downloaded from following link;

http://support.citrix.com/article/ctx111961

Citrix Protocol Driver Error

Today i faced a very complex problem. My Clients were complaining that they are are getting Citrix Protocol Driver Error. After initial troubleshooting i found that there were some http errors on my web interface servers. I restarted IIS on WIS but no luck. I restarted IMA service on Presentations servers but issue still remained same. It was strange that i am getting this error for all Applications published on different servers this means that this error is not server dependent.  i have tried Citrix article http://support.citrix.com/article/CTX106531 published on same issue and also tried disabling Session reliability http://support.citrix.com/article/CTX108439 but no luck. My Citrix environment consists of 2 Access gateway servers, 2 Web interface servers, 4 presentation servers and 1 license servers and we are using Netscaler device for load balancing. For narrowing issue i have disabled one web interface server from Load balancer and configured application to use only one presentation server but it didn’t solved the problem. I also restarted whole farm but no luck. Then i focused on Access gateway appliance and removed 1 appliance from Load balancing but issue remained same after that i enabled 1st device in Load balancing and removed second device from load balancing then after test i found that the issue is not occurring again and it is solved. I then logged on to the the troubled access gateway and found that this sever is not able to connect to the license server also this server is not configured to accept connections on port 80 only https. i am not sure why the sessions are not going to the other Access gateway which have correct configuration. I have to still fixed the licensing server connection issue but till now i haven’t got any complain from the user.