Category Archives: NetScaler

Protecting a URL using Citrix ADC responder policies

Recently a friend asked a question: How is it possible to bypass a responder policy. They knew it happened, but they could not reproduce. HTML- Encoding HTML Encoding is a stupid trick, used by hackers ever since. Any character may get encoded using a encoding table. So instead of using… Read more »

Virtual Apps and Desktops (XenApp) can’t connect through Citrix Gateway (NetScaler)?

It’s a problem coming up every now and then: I can’t connect to a certain Citrix VDA, but can connect to all/some others. If your problem is a more general one, continue reading here My first guess would always be a L4 problem, but “I opened up all firewalls”. Never… Read more »

Migrating a Citrix ADC /NetScaler config to an other box

I recently tried to migrate an existing configuration from one Citrix ADC (NetScaler) to the other. Both of them had been the same hardware (VPX running on KVM), used the same type of license (premium). If you move to different hardware please continue reading from here How to do Basically,… Read more »

Citrix ADC / NetScaler: two factors from outside, single factor inside

last update: September 25th 2019 I was recently asked: Johannes, is it possible to orun the same AAA server, from the inside with single factor, from the outside with two factor authentication? Of course it is. That’s how you do: Prerequisites My test environment contains of a lb vServer (lb_vsrv_colors)…. Read more »

Citrix ADC (NetScaler) 13: Pre-authenticating to TCP based services

photo by geralt (pixabay.com) last update: January 5th 2020 Recently I had to find a solution to block all connections to a TCP based service (SSH, TCP port 22), except of connections from IP addresses that pr-eauthenticated using a AAA vServer. This is something, most firewalls can do, but a… Read more »

How will a Citrix ADC (NetScaler) Web-application Firewall (WAF) change your ADC’s behaviour?

There is one thing different about a Citrix ADC WAF (Web Application Firewall) compared to most other features in Citrix ADC: It will affect your whole ADC deployment as soon as you turn it on. It you would, for example, turn on rewriting feature (enable feature RW), it would probably… Read more »

Setting languages for websites using Citrix NetScaler ADC

Last update: Sept. 26 2018 I recently had to set languages, using my Citrix ADC (NetScaler), for a website. My customer has several similar web-pages in different subdirectories. Naming scheme is like this: http://example.com/en for English http://example.com/de for German … There is currently a total of 12 languages. There had… Read more »

Concerns about Citrix NetScaler Web Application Firewall (WAF)

Let’s talk about a WAF, a Web Application Firewall on a Citrix NetScaler. What’s to be concerned off? Is it worth while considering a NetScaler to be your WAF? I do work for several companies, including Citrix Consulting Services. Recently I worked on some Web Application Firewall projects, so I… Read more »

Citrix ADC (NetScaler) as a SAML IDP and SAML SP

last update: 2019/09/05 Tested with NetScaler 11, Citrix ADC 12.1 and 13.0 I needed to use a Citrix ADC (NetScaler) both, as a SAML identity provider (IDP) and service provider (SP). So I set up my test environment accordingly. What my test environment looked like: You see, I created two… Read more »

Scheduling NetScaler commands for a specific time on Citrix NetScaler

Last update: 2018/03/27 Sometimes we have to schedule commands in a Citrix NetScaler. A good example would be: force HA failover It’s obvious, we don’t want to fail over during day time to not disconnect TCP connections, to not interrupt users. The best time would be something like 3:30 AM…. Read more »

Citrix NetScaler Logging and policy trouble shooting

Citrix NetScaler Logging and policy trouble shooting Some times it’s quite hard to understand what’s going on. There is so much mystics about policies. And it’s even harder to understand what went on (past tense). “Johannes, there had been several problems connecting to <any blabla application here>” “I’m sorry, I… Read more »

DDOS protection using Citrix NetScaler, 1st part

last update: February 21st 2018 How to protect a website using Citrix NetScaler? Well it seems to be easy. A nonsense question. We may use AppQoE (Application level Quality of Experience), a feature introduced with NetScaler version 10, so it’s quite an old feature. Let’s start. AppQoE is enterprise edition… Read more »

Binding many NetScaler Gateways to a content switching vServer on Citrix NetScaler, Method 1

last update: November 14 /2017 Or: The power of the ANY service type This is a work around for a well-known problem in NetScaler: Binding NetScaler Gateways to content switching vServers. This solution does not follow Citrix best practices. Avoid using it, if you can! My solution will work with… Read more »

Splitting up a NetScaler site using admin partitions

(a nice but partly failed try) Complex web applications may lead to complex NetScaler configuration. And sometimes an administrator may get lost troubleshooting complex websites, especially sites using content switching. This is an example of a real world website: The portal page is assembled of several independent web applications. Each… Read more »

Changing my Citrix NetScaler VPX based website from http to https and scoring an A+ in SSL labs test

Last update: July 12 2018 This blog is about NetScaler versions up to 12. January 2020: It’s pretty outdated by now, as some of the proposed encryption methods are outdated and there are serious concerns about TLS1.0 and TLS 1.1. Read Thomas’s blog from here. Citrix NetScaler load balancing and… Read more »