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Citrix ADC / NetScaler and TLS 1.3

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Last change: February 4th 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. The problem? It seems to be easy: Just tick...

SSH keys on Citrix ADC / NetScaler, a miracle?

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Thinking back to the end of my UNIX days, there had been something called SSH. It had been a replacement for telnet and had a nice feature called SSH keys. SSH keys were a safe and easy way to replace those tiresome passwords. I loved them! Almost at the same time, Windows came up and I lost contact with UNIX. I always hoped, IT will switch over to Linux, but it never happened and my UNIX...

Migrating parts of a Citrix ADC / NetScaler configuration from test site to production site

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This is an old problem with Citrix ADC / NetScaler: You should test all changes in test-site first and move them to production, or synchronise production site and disaster recovery site. Unfortunately, there is no built-in mechanism to synchronize configuration. So, over time, these sites will start differing, a very unwelcome state. This is especially true for WAF, as applications tend to change...

Which cyphers to use on a Citrix ADC /NetScaler?

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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...

A simple way for a Citrix ADC (NetScaler) to respond with a 404 not found

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I am a big fan of cheating if it comes to security. Giving wrong answers to questions may be misleading and will direct attackers into the wrong direction. This will cost time and, at the same time, rise the risk of being caught red-handed. If someone attacks a website, he has to be discrete and fast. Discrete to not get trapped, quick to be long gone in case the owner learns about the attack. So...

A quick way to expand performance on Citrix (NetScaler) Gateways

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This is Corona time, and Corona drives virtualization like nothing else did before. I recently had to fix issues with remote access. Usually, it would have to handle round about 1,500 users, but now, the number of users increased to 15,00, so ten times as much. The existing MPX-11500 could not handle all these connections, latency was way to high. Our customer needed a quick resolution, as every...

Using Geo-Location in Citrix ADC / NetScaler

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Last update: 2021-02-18   There are several use cases for geo-location information in Citrix ADC / NetScaler. It may be helpful with WAF logs. I am European, I won’t spend much time on a positive, if the log comes from North Korea, but I would consider it to be a “false positive”, if it comes from Germany, Italy or Sweden. Even though I would not consider it to be secure...

Are there Syslog events coming from partitions?

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© Wikipedia, Creufop There seems to be no way to log events inside partitions, even though there are settings for logging and configuration seems to be right. They are exactly the same as in default partition. Syslog server is 127.0.0.1, so the local machine. Everything seems to be perfect. But /var/partitions/<partitionname>/log will remain empty. Why? Well, the syslog-server is 127.0.0.1...

Creating Certificates for Citrix ADC (NetScaler)

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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 /...

I got rewarded CTA!

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Two weeks ago Citrix sent me an email saying that they had awarded me as CTA, a Citrix Technology Advocate. It had been released today. It is a great honour to me! I am one of very few Citrix technicians worldwide who have received this award, the only one in Austria. I also known many of the existing CTAs, and they are all people that I appreciate, some of whom I am friends with, people who I...

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