Debian

[SOLVED] The following signatures were invalid: EXPKEYSIG B188E2B695BD4743 DEB.SURY.ORG Automatic Signing Key

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Here is the solution if you've got the following error message when updating package lists on Debian (apt-get update): The following signatures were invalid: EXPKEYSIG B188E2B695BD4743 DEB.SURY.ORG Automatic Signing Key The sury.org Debian package repository has changed its package signing key. To fix the error, just download the new key: apt-key adv --fetch-keys https://packages.sury.org/php/apt.gpg Finally, ... Read more

Postfix Submission vs. Submissions (SMTPS) port

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Postfix submission vs submissions port

In Postfix configuration, particularly on Debian and Ubuntu systems, you might come across terms like "submission" and "submissions" when looking into the Postfix /etc/postfix/master.cf file. This article explains the differences and use cases for both ports. Postfix Submission Port 587 This is the standard port for email submission as defined by the Internet Message Access ... Read more

How to enable port 587 (submission) in postfix

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Postfix Port 587

pSome internet access providers have port 25 disabled in their routers to prevent spam. If you run your own email server in a data center, you might have to enable the submission port (587) in postfix to be able to send emails from your local email client to your own mail server. Enable Submission Port ... Read more

How to convert RPM software packages to Debian (.deb)

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The world of Linux is diverse, Linux distributions using different package management systems. RPM (Red Hat Package Manager) and Debian's DEB are two of the most common package formats. Occasionally, users of Debian-based systems might need to install software that's only available in the RPM format. This guide covers converting RPM packages to DEB format, ... Read more

How to open winmail.dat files on Ubuntu and Debian Linux

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Open winmail.dat on Linux

Winmail.dat files are a unique file format utilized primarily by Microsoft Outlook. These files serve as containers for attachments sent through emails formatted in rich-text. This format can cause compatibility issues, particularly when users of non-Microsoft email clients, such as those on Linux systems, receive attachments. What is a Winmail.dat File? When an Outlook user ... Read more

How to set PassivePortRange and PassiveIP in pure-ftpd on Debian and Ubuntu Linux

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If you run a firewall on your Linux server and want to use passive FTP connections, you have to define the passive port range in pure-ftpd and your firewall to ensure that the connections don't get blocked. The following example is for pure-ftpd on Debian or Ubuntu Linux and ISPConfig 3. Set Passive Port Range ... Read more

Yarn Installation on Debian Linux

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YARN package manager is a tool for managing yarn. The acronym stands for “Yet Another Resource Negotiator”, and that is what the package manager does: it negotiates with other packages to determine which will consume resources and when without user intervention. The design of this system was inspired by Node’s npm and Python’s pip, but ... Read more

How to Install Mono on Debian Linux

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Mono Framework is an open-source software framework that can be used to create all kinds of Server and Desktop applications, incl. games. Mono Framework is dependency-free (No C++ compiler required) and compatible with Windows, Linux, Mac OS X and FreeBSD. Mono Framework started as a fork of Microsoft’s .Net Framework v1.0 but now has become ... Read more