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today's howtos
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APNIC ☛ Decoding TCP SYN for stronger network security
Analysing Transmission Control Protocol (TCP) SYN segments, the initial step in the TCP three-way handshake, can reveal patterns and anomalies in network traffic, providing insights into potential threats. In this article, we use data collected from NETSCOUT honeypots, which are systems designed to capture unsolicited Internet traffic, to examine TCP SYN segments. By focusing on packet headers, as network routers typically do, we explore trends in source addresses, IPv4 time-to-live (TTL) values, and TCP header lengths. This narrow perspective demonstrates how even limited packet data can yield actionable intelligence without delving into payloads or complex attack patterns.
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Vermaden ☛ Crucial FreeBSD Toolkit
While FreeBSD is similar in many concepts to other UNIX systems or to Linux – its good to know exact commands and solutions for various needs.
Today I would like to share all of them – after using FreeBSD for about 20 years – both privately and professionally.
The Table of Contents looks as follows.
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University of Toronto ☛ Linux 'exportfs -r' stops on errors (well, problems)
Although it's not documented and not explicit in 'exportfs -v -r' (which will claim to be 'exporting ...' for various things), I have an important safety tip which I discovered today: exportfs does nothing on a re-export if you have any problems in your exports. In particular, if any single file in /etc/exports.d has a problem, no files from /etc/exports.d get processed and no exports are updated.
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University of Toronto ☛ Systemd user units, user sessions, and environment variables
A variety of things in typical graphical desktop sessions communicate through the use of environment variables; for example, X's $DISPLAY environment variable. Somewhat famously, modern desktops run a lot of things as systemd user units, and it might be nice to do that yourself (cf). When you put these two facts together, you wind up with a question, namely how the environment works in systemd user units and what problems you're going to run into.
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PCLinuxOS Magazine ☛ Typst Cookbook: Part Three
The first printed books, or incunabula (from the Latin word incunabulum ['cradle' or 'swaddling clothes', hence 'beginning']), did not have title pages. The text simply begins on the first page, and the book is often identified by the initial words—the incipit (from the verb incipere ['to begin'])—of the text proper. Other older books may have bibliographic information in the colophon (derived from the Greek word κολοφών ['summit' or 'finishing touch']) at the end of the book.
Early printers produced the pages of a text: the text block. The text block was sold unbound, as a stack of pages. Since print shops were physically demanding, messy environments, the first page of a text block often became scuffed. Printers began making cover pages with some basic identifying information, for convenience and protection of the actual pages. This cover page gradually evolved into a full title page with publication details as well as the author and title.
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PCLinuxOS Magazine ☛ Wiki Pick: Restore Grub2
Your bootloader may end up corrupt or overwritten by another operating system due to many factors such as user error, power loss or malware etc. In such situations, you may find yourself in search of a way to restore your bootloader to a state in which it will normally load your favorite PCLinuxOS.
To fix or restore the GRUB2 bootloader on your PCLinuxOS system you will need to boot a recent PCLinuxOS LiveOS then you can choose one of the 2 methods below depending on whether you prefer using the command-line or graphical user interface.