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ever since the initial tuning of the FreeBSD TCP/IP stack around version 4.x, I’ve found myself occasionally tinkering with the contents of /etc/sysctl.conf just to fine-tune things, you know over time, numerous changes have been made to the FreeBSD TCP/IP stack, including the introduction of modularity. however, MacOS X, being based on FreeBSD, is more conservative and lacks certain options. therefore, on my MacOS systems, I make use of the following /etc/sysctl.conf configuration: ...

as I’m installing FreeBSD boxes and VMs left and right, I typically do some initial setup before doing anything else. while some use cases call for additional ports to be installed (like bird or routinator), there’s pretty standard “intro”. first, make sure the packages themselves are up to date: sed -i '' s/quarterly/latest/g /etc/pkg/FreeBSD.conf pkg upgrade this will trigger initial pkg install. then, it’s my personal minimum set of packages: pkg install htop bmon mtr-nox11 screen wget doas git-lite as ZFS is only filesystem you should be using ( ;) ) and this is not some NAS system, I typically disable access time marking to speed up VM filesystem operations a bit: ...

if you have to pack a lot of things, using sheer power of modern multi-core/multi-threaded CPUs may come handy. unless… the tools you’re using are not enabling that by default, and you suffer running everything on one core/thread. as I spend most of my time recently with FreeBSD and MacOS the tools I typically use are command line. therefore, for every gzip - consider using pigz. and for bzip2 - consider using pbzip2. ...

BGP Blackholing is back - with small steps (‘better done than perfect’). go ahead and visit the current project page with “quick howto”. happy blackholing!

nice addition to recent IOS-XE images is the info in BGP view when the peak number of prefixes was received: rtr-edge#sh bgp ipv4 unicast summary [...] 6807 received paths for inbound soft reconfiguration BGP activity 1126906/107856 prefixes, 1337822/171863 paths, scan interval 60 secs 878960 networks peaked at 15:02:09 Jan 29 2022 CET (22:53:01.065 ago) [...] rtr-edge#sh bgp ipv6 unicast summary [...] BGP using 102467162 total bytes of memory BGP activity 1126898/107856 prefixes, 1337806/171843 paths, scan interval 60 secs 140720 networks peaked at 05:46:19 Jan 29 2022 CET (1d08h ago) [...] while logged in over CLI you may glance at this info without needing to check your monitoring systems (you have them, right?). ...

one of the very old tricks, that’s even documented is how to simulate ctrl-break on newer PCs to break into ROMMON during router/switch boot. instead of fighting with SecureCRT on MacOS, I just used it recently. basically, you: disconnect terminal from the device turn device off set terminal to 1200 (yes, you read this right), 8N1 and no flow control turn device on press SPACE for 10-15 seconds (basically, until your terminal drops out some unreadable characters) reconfig terminal to 9600 8N1 and you should be in ROMMON yes, I’m old. ...

if you’re not accustomed to reading release notes for your favorite platform (Nexus NX-OS in this case), probably you already overlooked that starting with 10.1(2) there’s 2-stage commit system, known from IOS XR. what does that mean, really? that doing changes over CLI, directly in the parser, you can edit/add/remove whole blocks of configuration before committing them to running/actual configuration. so in case when you edit interface IP addressing (always touchy moment, specially for devices you’re 300km away for example) the session could look like this: ...

I was invited by Adam Lange and Adam Haertle to share my story in “rozmowa KONtrolowana” podcast (in Polish). I’d like to thank both of them and of course all of participants for invitation, leading it, questions and nice way to spend time in familiar, geeky environment :) now - just view/listen to it your favorite format :)

if you’re not first-time visitor here, likely you know already I’m reading a lot of books. a lot? after years of carefully considering and accumulating books, I finally fulfilled one of my early dreams: to have a wall full of shelves dedicated to storing my book collection (as depicted in the opening picture of this post, although some packages obstruct the view - my apologies for that). now, what exactly constitutes “a lot” of books? for me, it means reading around 2-3 books per week, resulting in an average of over 100 books per year staying on shelves. of course, this is just an average figure. during vacations, I tend to indulge in more reading material (and sometimes end up buying additional books when I exhaust my supply). moreover, due to the pandemic, I’ve been reading even more than usual. however, it’s not a race to break records. reading simply becomes second nature over time. you can start at your own pace with any book that piques your interest. and see how deep the rabbit hole goes ;) ...