Mitigating Docker Build Issues on Older glibc Hosts
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Mitigating Docker Build Issues on Older glibc Hosts

When running newer operating systems as Docker containers on older host systems—such as Ubuntu 20.04 or CentOS 7—a compatibility issue arises due to a new glibc call (clone3) not translating correctly to the older glibc (<=2.34) of the host system, resulting in the call being incorrectly translated, and blocked. One workaround to this issue involves…

SSH Client improvements

SSH Client improvements

This article is going to concentrate several SSH client related topics and optimisations I have implemented. Amongst are: SSH client modular configuration Initially, the configuration for SSH client should be present (per-user) in the user’s home directory, under .ssh/config. I believe that this configuration file is not modular enough, and when you want to add/edit/remove…

Oracle Linux 8 RPM installation broken
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Oracle Linux 8 RPM installation broken

I got the following error message when attempting to upgrade RPM packages: Oracle Linux 8 introduced a bug with a package called rpm-plugin-selinux (details: rpm-plugin-selinux-4.14.3-28.0.1.el8_9) which prevents RPM packages from being installed correctly, either by dnf/yum or manually. The solution, as shown in this Oracle community forum is to downgrade the package rpm-plugin-selinux like that:…

Cisco AnyConnect on Linux solution to “Authentication failure due to problem verifying server certificate” error message

Cisco AnyConnect on Linux solution to “Authentication failure due to problem verifying server certificate” error message

This is a very technical and a limited solution to Cisco AnyConnect issue with unknown certificate on Linux (Ubuntu 22.04). AnyConnect version is 4.10. I hope this post will help others with a similar problem. The issue is around SAML authentication (an embedded web browser attempting to complete the authentication process), and its failure to…

Allow Postfix to call custom scripts by using mail aliases
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Allow Postfix to call custom scripts by using mail aliases

Using custom mail aliases to run scripts is an existing practice. However, on modern Linux distributions it is blocked as a security risk. Following Postfix common guidelines do not allow for it to run the scripts. It reports the script as called, however – it does actually nothing. This has been verified on Oracle Linux…