Blocking requests to the IP address in SSL vServers on Citrix NetScaler ADC


This might sound like an idea from an overcautious paranoid guy. But it’s not: My customer is in a very sensitive business. The problem Somebody may scan the internet for open ports and, by random, connect to my customer’s IP. This person will send a request and see my customer’s gateway. He might get curious, even though the gateway is not branded at all and the hostname is not...

Citrix ADC / NetScaler: How to find out, which users use which Ciphers?


There is something I frequently get asked for: How can we find out, which users use which ciphers? Will Citrix ADC show this information? Does ADM show it? A simple answer would be: No chance, ADC can’t do it at all. ADM – however – can do. If you don’t like ADM (I’d wonder why) you can’t. Let’s not make things that simple. We all are engineers. The word...

Citrix ADC / NetScaler and TLS 1.3


Last change: December 21st 2021. Thanks to Dirk Bautz! This is the 2nd part to my article “Which ciphers to use on a Citrix ADC /NetScaler?” This one had been about TLS versions up to 1.2 only. Moving from TLS 1.2 to TLS 1.3 on an existing Citrix ADC ( NetScaler) may be a big step with some obstacles to overcome. It needs some investigation. Why TLS 1.3? Simple: TLS 1.3 is faster, as...

Which cyphers to use on a Citrix ADC /NetScaler?


latest update: May 5th 2021 Recently I found myself in a discussion with another Citrix architect about the number of cyphers needed. I had added as little as fife cyphers to a cypher group. He thought this is not enough. Why should we have many cyphers into a cypher group? To be honest, I don’t understand. It may look flexible, feature-rich and mighty. Customers may get impressed...

Creating Certificates for Citrix ADC (NetScaler)


The way we create certificates has not changed significantly over the years. Only the wizard is subject to a certain change. This blog is based on Citrix ADC 13, elder versions don’t differ significantly. The following steps are necessary to create a certificate: Generate the key pair Create the certificate-signing request Generate the certificate (either using Citrix ADC /...

Redirecting a user to a SSL page (preserving the URL)


I’m just setting up a Web Application Firewall on a Citrix NetScaler 11.1 for a costumer’s shop. My costumer mandated: most of the website has to be available via HTTP. However we don’t want to expose sensitive information to the internet, so we had to create a policy redirecting users to SSL whenever needed. So how can we do this? First of all, I had to find out: which...

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. Find later versions here 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 content switching servers will only score an C in quality labs SSL...

Making a NetScaler Gateway on NetScaler 11 a bit more secure


last update February 7th 2017 There are never versions about SSL-settings We have previously created a NetScaler Gateway on our NetScaler 11. That’s great! Time to check if it’s secure. I usually use SSL labs SSL test, a widely used tool to test the security of a website. I have an other blog about NetScaler virtual servers (contentswitching and loadbalancing SSL offloading servers)...

Enabling ECDHE ciphers in NetScaler 10.5


last update: February 7th 2017 Similar but newer posts: Changing my Citrix NetScaler VPX based website from http to https and scoring an A+ in SSL labs test and Making a NetScaler Gateway on NetScaler 11 a bit more secure ECDHE Ciphers, this means, Elliptic curve Diffie–Hellman type of cyphers, add additional security to a NetScaler. If we want to use this kind of cyphers we need to create a DH...

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