lukasz.bromirski.net

weekend project - cisco bgp dump syslog decoder

weekend project - pihole-like dashboard for NLNet Labs unbound caching resolver

weekend project - a Rust implementation of file storage in travelling packets

my name is Łukasz Bromirski. at IS-Wireless, I oversee product and sales as CPO and CSO. we deliver sovereign, high-performance software for private 5G/6G networks. the stack secures defense customers, but also powers critical communication in civilian wo…

when dealing with disks that power your OS, it’s good to understand that the best way to deal with them is not to deal with them at all - store everything in memory and be done with that. unfortunately, data has to be loaded from somewhere. here comes Int…

one of the common issues with OpenBGPd ports in FreeBSD is that they don’t have FIB integration, and therefore prefixes received over BGP connections won’t be installed in system routing table. outside of route server and looking glass, that makes OpenBGPd

long time ago, we decided with Piotr Jablonski to create and run our own CCIE Service Providers bootcamp. since then, Cisco didn’t enter this market through autorised trainings. while Piotr ventured to world of containers (and security), I’m personally st…

a great book for fans of digging into the history of spaceflight and various crazy projects. the moon and space bases when it comes to the ’nazi scum’, they are mainly represented by Wernher von Braun, an SS officer whom the Americans decided to whitewash…

when working with FreeBSD daily, the ability to mount remote filesystems is super handy. if you’re into NFS, this post isn’t for you — in this post I’m more interested in SMB (CIFS) and SSH (yep, really!).

a very interesting read to check out, especially if you’re used to books written by networking vendors. this one offers a different perspective on the Internet — a mix of academic insight and practical with real-world examples. it’s a short book, but it d…

“in light of the current situation” following polish presidential elections (and the sloppy government reaction to proven anomalies in the voting system), I decided to put aside some non-essential activities and dive back into reading—this time on topics…

what it’s all about?

if your usual apple -> system settings -> general -> software update doesn’t want to show that there’s update available, and you absolutely, positively know there is one, you can “push” MacOS to refresh list of available updates. to do so, go to terminal…

you may have missed that, but IANA decided to properly delegate service.arpa subdomain, just like they did previously to home.arpa - to avoid DNSSEC breakage. if you’re using BIND to serve your own AS112 instance, it’s enough to add following line: zone "…

as you work through various configurations (and - inevitably - troubleshooting), you may end up in situation where because of limited visibility (“hey, it’s customer device!”)

books i wrote CCIE Service Provider v5.0 workbook - coauthored with Piotr Jabłoński; we’re also running special promotion with our late friend Nicholas Russo that can be found here books i translated (to Polish) Słownik terminów i skrótów sieciowych, Wars…

if you want to get really deep dive into network technologies, take a look below - you may find what you need. if you have further questions or need something special - reach out over e-mail lukasz|at|bromirski.net dedicated bootcamps CCIE Service Provide…

those of you working on a daily basis with configuration and reconfiguration of network devices are likely to hit various caveats and surprises. sometimes, we hit problems that take hours to troubleshoot. route?

I’m not using any wonderful scripts on my website, that would measure your “responsiveness” or encourage you to subscribe to newsletters.

if you have read my previous pieces about my home network, you know well my core switch is Nexus 93180YC-EX. you know… home, core switch. anycasted services at any point in time I have a number of DNS (and DHCP) servers available, all reachable via either…

if, like me, you would like to use RbPi 5 and FreeBSD at the same time, simply copying the 13.2/14.0 image to the SD card is not enough. in addition to the already known one (where rdiskX contains the ID of your SD card/USB key - beware of accidentally ov…

presentations from different events (mind it, most of them are in Polish!)

below you can see some of the community projects I created/actively maintaining: AS 112 - a worldwide project to sinkhole RFC 1918 DNS traffic locally within countries and regions to avoid slamming DNS root servers; I’m maintaining three AS112 servers in…

what it’s all about?

long, long time ago I’ve written a post about how to authenticate with keys via SSH to devices working under the control of IOS XE and ASA/FTD. since the big boys usually work with IOS XR, below is a quick guide on how to import keys to this system in ver…

I’m not a fan of such ‘solutions’ because they hardly qualify as genuine fixes. however, if you find yourself working in MacOS-heavy environment that’s plagued by radio frequency interference, you’ve probably experienced the erratic behavior of Bluetooth-…

quick note for those spending weekends on labbing - if you want to log info (from Syslog for example), and the management interface is in separate VRF (very good idea), you need to configure VRF in two, or even three (if you count VRF definition itself) d…

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

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 su…

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 ti…

a set of old projects, I was taking care of in the past. notice it’s all in Polish. tutorials, howtos, articles (nie)oficjalny Cisco FAQ PL pierwszy z projektów, którego miałem zaszczyt zostać koordynatorem – nieoficjalne Cisco FAQ PL. projekt stanął, miał

what it’s all about?

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, 1337822/1718…

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

every now and then, I like to cover some technology gadgets here, especially when I’m genuinely delighted with them. for instance, a while back, I wrote about the Bose QC 35 wireless headphones (and how I stubbornly resisted them for so long, despite spen…

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?

I was invited by Adam Lange and Adam Haertle to share my story in “rozmowa KONtrolowana” podcast (in Polish).

if you’re not first-time visitor here, likely you know already I’m reading a lot of books. a lot?

as I get old, seems I’m missing obvious signals. my logs were screaming about it, friends made touchy comments… and nothing. after moving to hugo, despite the fact it has built-in RSS feed support, I somehow missed that completely. fortunately, it’s enough

Eliot Higgins has achieved something remarkable by establishing a highly influential organization right from his own kitchen. this organization is dedicated to combatting the chaos caused by rampant disinformation and falsehoods disseminated by individual…

if you, like me, just love corporations that blatantly lie in your eyes about “protecting your privacy”, you’re ready to spend some time to make their lives as hard as possible. one of the new ideas is Google FLoC - Federated Learning of Cohorts. great co…

one notable advantage of possessing expertise in IPv6 is the inherent distinction it maintains from IPv4, as they are entirely separate protocols. take a moment to contemplate this concept. pay close attention to the notion of IPv6 being entirely separate…

my journey with expert-level Cisco certification began already quite far long time ago - 15 years. and with Cisco certification overall - even couple years earlier than that.

the book did a lot of noise, being quoted everywhere even before it was published. as part of the marketing before release, they even did limited publishing in parts in partnership with wired. but… the book is bad. simply as that. if you expected Tom Clan…

we are all dealing daily with the eponymous “bullsh*t truth” and unfortunately we are inundated with it. we live in an age where opinions are treated as facts, and anyone who has access to the “mass media” suddenly becomes a great philosopher, thinker and…

one of the most common, but at the same time easiest problems to solve, when you’re working with FreeBSD system installed on too small disk is rebuilding the system. in my specific case, it was very old i386 system initially installed around release 6 on a

after I decided to save you and myself from spying eyes of Google Analytics, I don’t really look at my blog web statistics. just glancing over logs shows you’re reading - and that’s about all if you ask me.

FreeBSD just migrated to git, and while handbook is being updated, you can do the migration yourself. first of all, move original src directory (if you’re synchronizing over SVN) away, along with customized kernel config file. for my deployments I do: mv…

if you happen to have more than one internet connection and they have different usable bandwidths - which is no longer a rarity today - it becomes interesting element in network design. how would you use these links optimally?