Solved: VDA client unattended install failure.


When you’re solving the same problem after a couple of months it’s probably a good idea to write a post about it so the solution is close at hand. When you perform an unattended install of VDA client from the 7.x XenApp/XenDesktop media the installation may fail, after this first failure all other attempts will fail […]

Solved: Netscaler VPX (on VMWare) Problem.


During my latest project I ran into a problem where Netscaler VPX stops responding to any sort of request. Logon to Netscalers management interface: Netscaler immediately stops responding. Connect to Netscalers Access Gateway VPN server: Netscaler immediately stops responding. Connect to Netscalers Access Gateway Logon Interface: Netscaler immediately stops responding. The state of the netscaler is as follows: Netscaler is no longer reachable via […]

HOW TO: Netscaler 10.5 – Change Password / Secure LDAP configuration


During my current project I had to build a Netscaler cluster for Access Gateway functionality. After initially configuring the Access Gateway vServer I noticed that user account that are marked for “Change Password on next Logon” could not authenticate not via Access Gateway Logon Page nor Via Dell Wyse ThinClient that are configured for StoreFront […]

Windows 2012 R2: Black logonscreen after App-V 5 (SP2) Client installation


While I was building a proof of concept for my customer I ran into some issues that where seemingly unrelated. I was building a brand new Windows 2012 R2 / XenApp 7.5 environment including RES Automation Manager, RES Workspace Manager and App-V 5 (SP2). After installing and testing the core XenApp infrastructure, I started to […]

Netscaler Patching and Heartbleed Information

After the publicity of the latest OpenSSL vulnerability CVE-2014-0160 (aka Heartbleed). I’ve investigated if Netscaler’s firmware was vulnerable to this vulnerability. Soon I found out that Netscaler’s software is NOT vulnerable. But during my investigation I noticed that the OpenSSL implementation is very old (2004). This raised some questions like: Why this old version is still actively […]

Juniper SA VPN Appliance vs. Heartbleed OpenSSL vulnerability

According to some tests on SSL Labs Juniper SA appliances (and client software) ARE vulnerable to the OpenSSL Heartbleed vulnerability. This is confirmed by Juniper in this support document. According to Juniper’s support document: PROBLEM: The TLS and DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly handle Heartbeat Extension packets, which allows remote attackers to […]

Netscaler vs CVE-2014-0160 (Heartbleed) OpenSSL vulnerability

Yesterday a lot of attention was created about the latest OpenSSL vulnerability (CVE-2014-0160). This vulnerability exposes a lot of SSL implementations to a great risk because OpenSSL is a very popular SSL implementation and used in a great range of Unix/Linux based application and appliances. Being very busy with Citrix Netscaler lately I immediately recognized the great potential […]

Shame on Me!

Shame on me, it has been more than a year between blogposts. It has been a busy year so that’s good. Hopefully I will find some time next weeks to start writing again.

SCRIPT: Check ICA Listener response


Last week I was troubleshooting at a customer which was experiencing some “random” periods in which end users could not login at all. When looking at the Load Evaluator I noticed the least loaded server in those periods were the same. When trying to logon to the server through ICA, the server sits forever at […]

Send Message to User Limitations


Today I received a question from a customer who wanted to send “Large” message to all XenApp users in the farm. They asked me what the maximum number of characters was that you can send to a user. I honestly did not have a clue and answered to the client that I was not aware […]