Author Archives: Ivan Pepelnjak
Author Archives: Ivan Pepelnjak
Julia Evans published another phenomenal blog post, this time focused on blogging myths including:
Dip Singh published an excellent primer on communication fundamentals including:
Even if you don’t care about layer-1 technologies you MUST read it to get at least a basic appreciation of why stuff you’re using to read this blog post works.
Dip Singh published an excellent primer on communication fundamentals including:
Even if you don’t care about layer-1 technologies you MUST read it to get at least a basic appreciation of why stuff you’re using to read this blog post works.
Andrei Robachevsky asked me to spread the word about the new MANRS+ customer survey:
MANRS is conducting a survey for organizations that contract connectivity providers to learn more about if and how routing security fits into their broader supply chain security strategy. If this is your organization, or if it is your customers, we welcome you to take or share the survey at https://www.surveymonkey.com/r/BDCWKNS
I hope you immediately clicked on the link and completed the survey. If you’re still here wondering what’s going on, here’s some more information from Andrei:
Andrei Robachevsky asked me to spread the word about the new MANRS+ customer survey:
MANRS is conducting a survey for organizations that contract connectivity providers to learn more about if and how routing security fits into their broader supply chain security strategy. If this is your organization, or if it is your customers, we welcome you to take or share the survey at https://www.surveymonkey.com/r/BDCWKNS
I hope you immediately clicked on the link and completed the survey. If you’re still here wondering what’s going on, here’s some more information from Andrei:
Years ago I wrote an article describing how EIGRP stub routers work and how you should use them in redundant remote sites to make sure link- or node failures don’t result in partial connectivity. That article is now available on ipSpace.net; I hope at least someone will find it useful. I know it’s about ancient technology, but then people are still running COBOL on mainframes.
Years ago I wrote an article describing how EIGRP stub routers work and how you should use them in redundant remote sites to make sure link- or node failures don’t result in partial connectivity. That article is now available on ipSpace.net; I hope at least someone will find it useful. I know it’s about ancient technology, but then people are still running COBOL on mainframes.
While preparing the Internet Routing Security webinar, I stumbled upon RFC 7908, containing an excellent taxonomy of BGP route leaks. I never checked whether it covers every possible scenario1, but I found it a handy resource when organizing my thoughts.
Let’s walk through the various leak types the authors identified using the following sample topology:
While preparing the Internet Routing Security webinar, I stumbled upon RFC 7908, containing an excellent taxonomy of BGP route leaks. I never checked whether it covers every possible scenario1, but I found it a handy resource when organizing my thoughts.
Let’s walk through the various leak types the authors identified using the following sample topology:
Stefano Sasso added two new Junos platforms in netlab release 1.5.4:
There are also the usual bug fixes, and we moved the documentation to netlab.tools.
Stefano Sasso added two new Junos platforms in netlab release 1.5.4:
There are also the usual bug fixes, and we moved the documentation to netlab.tools.
Large language models (LLM) – ChatGPT and friends – are one of those technologies with a crazy learning curve. They look simple and friendly (resulting in plenty of useless demoware) but become devilishly hard to work with once you try to squeeze consistent value out of them.
Most people don’t want to talk about the hard stuff (sexy demoware results in more page views), but there’s an occasional exception, for example All the Hard Stuff Nobody Talks About when Building Products with LLMs describing all the gotchas Honeycomb engineers discovered when creating a LLM-based user interface.
Large language models (LLM) – ChatGPT and friends – are one of those technologies with a crazy learning curve. They look simple and friendly (resulting in plenty of useless demoware) but become devilishly hard to work with once you try to squeeze consistent value out of them.
Most people don’t want to talk about the hard stuff (sexy demoware results in more page views), but there’s an occasional exception, for example All the Hard Stuff Nobody Talks About when Building Products with LLMs describing all the gotchas Honeycomb engineers discovered when creating a LLM-based user interface.
Security researches found another ICMP redirect SNAFU: a malicious wireless client can send redirects on behalf of the access point redirecting another client’s traffic to itself.
I’m pretty sure the same trick works on any layer-2 technology; the sad part of this particular story is that the spoofed ICMP packet traverses the access point, which could figure out what’s going on and drop the packet. Unfortunately, most of the access points the researchers tested were unable to do that due to limitations in the NPUs (a fancier word for SmartNIC) they were using.
Security researches found another ICMP redirect SNAFU: a malicious wireless client can send redirects on behalf of the access point redirecting another client’s traffic to itself.
I’m pretty sure the same trick works on any layer-2 technology; the sad part of this particular story is that the spoofed ICMP packet traverses the access point, which could figure out what’s going on and drop the packet. Unfortunately, most of the access points the researchers tested were unable to do that due to limitations in the NPUs (a fancier word for SmartNIC) they were using.
After discussing the backend and CPE architecture in a typical SD-WAN solution in the SD-WAN Overview webinar, Pradosh Mohapatra mentioned a few SD-WAN security aspects, focusing on typical attack vectors and the usual mitigations.
After discussing the backend and CPE architecture in a typical SD-WAN solution in the SD-WAN Overview webinar, Pradosh Mohapatra mentioned a few SD-WAN security aspects, focusing on typical attack vectors and the usual mitigations.
Got this question from a networking engineer attending the Building Next-Generation Data Center online course:
Has anyone an advice on LACP fast rate? When and why should you use it instead of normal LACP?
Apart from forming link aggregation groups, you can use LACP to detect link- and node failures (more details). However:
Got this question from a networking engineer attending the Building Next-Generation Data Center online course:
Has anyone an advice on LACP fast rate? When and why should you use it instead of normal LACP?
Apart from forming link aggregation groups, you can use LACP to detect link- and node failures (more details). However:
Distributed systems are complicated. Add networking to the mix, and you get traumatic challenges like the CAP theorem and Byzantine fault tolerance. Most of those challenges are unknown to engineers who have to suffer through the vendor marketing presentations, making it hard to determine whether the latest shiny gizmo works outside of PowerPoint.
I started collecting articles describing distributed-system gotchas years ago, wrote numerous blog posts on the topic in the heydays of the SDN Will Save the World lemming run, and organized them into the Distributed Systems Resources page.