Neat: due to some nuclear weapons treaty, rocket communications are transmitted more or less in the clear, and a group of enthusiasts have decoded additional internal sensor readings & pictures from spacex, but also some chinese ones(?). Kind of surprising that there’s not more industrial espionage going on, or if there is, others don’t seem to suspiciously catch up with spacex.
Tag: networking
NAT traversal
If the IP address is correct, our only unknown is the port. There’s 65535 possibilities… Could we try all of them? At 100 packets/sec, that’s a worst case of 10 minutes to find the right one. It’s better than nothing, but not great. And it really looks like a port scan (because in fairness, it is), which may anger network intrusion detection software.
We can do much better than that, with the help of the birthday paradox. Rather than open 1 port on the hard side and have the easy side try 65535 possibilities, let’s open, say, 256 ports on the hard side (by having 256 sockets sending to the easy side’s ip:port), and have the easy side probe target ports at random.
If we stick with a fairly modest probing rate of 100 ports/sec, 50% the time we’ll get through in under 2 seconds. And even if we get unlucky, 20 seconds in we’re virtually guaranteed to have found a way in, after probing less than 4% of the total search space.
Open RAN
Open RAN looks like a great alternative to all the proprietary 5G nonsense.
contrary to the information being published by legacy RAN vendors, Open RAN is real; Open RAN has been deployed in commercial networks today; the Open RAN community is thriving; the cost savings are being realized; and operational performance requirements and KPIs are being met.
BGP hacking
This article will show how this hijacking works, and how China employs its conveniently distributed points of presence (PoPs) in western democracies’ telecommunications systems to redirect internet traffic through China for malicious use. It will show the actual routing paths, give a summary of how one hijacks parts of the internet by inserting these nodes, and outline the major security implications.
First Cyberattack in 1834
The Blanc brothers traded government bonds at the exchange in the city of Bordeaux, where information about market movements took several days to arrive from Paris by mail coach. Traders who could get the information more quickly could make money by anticipating these movements. Some tried using messengers and carrier pigeons, but the Blanc brothers found a way to use the telegraph line instead. They bribed the telegraph operator in the city of Tours to introduce deliberate errors into routine government messages being sent over the network. The telegraph’s encoding system included a “backspace” symbol that instructed the transcriber to ignore the previous character. The addition of a spurious character indicating the direction of the previous day’s market movement, followed by a backspace, meant the text of the message being sent was unaffected when it was written out for delivery at the end of the line. But this extra character could be seen by another accomplice: a former telegraph operator who observed the telegraph tower outside Bordeaux with a telescope, and then passed on the news to the Blancs. The scam was only uncovered in 1836, when the crooked operator in Tours fell ill and revealed all to a friend, who he hoped would take his place. The Blanc brothers were put on trial, though they could not be convicted because there was no law against misuse of data networks. But the Blancs’ pioneering misuse of the French network qualifies as the world’s first cyber-attack.
Learning by reproducing
Students taking Stanford’s Advanced Topics in Networking class have to select a networking research paper and reproduce a result from it as part of a 3-week pair project. At the end of the process, they publish their findings on the course’s public Reproducing Network Research blog. It’s well worth having a look around the blog: the students manage to achieve a lot in only 3 weeks! In the last 5 years, 200 students have reproduced results from 40 papers.
In ‘Learning networking by reproducing research results’ the authors explain how this reproduction project came to be part of the course, what happens when students try to reproduce research, and the many benefits the students get from the experience. It’s a wonderful and inspiring idea that I’m sure could be applied more broadly too.
Wifi is flaky
Wifi connections fail an astonishing 45% of the time. And the time they take is hugely variable, with 15% of connections taking more than 5 seconds.
BBR
This commit implements a new TCP congestion control algorithm: BBR (Bottleneck Bandwidth and RTT). A detailed description of BBR will be published in ACM Queue, Vol. 14 No. 5, September-October 2016, as “BBR: Congestion-Based Congestion Control”. BBR has significantly increased throughput and reduced latency for connections on Google’s internal backbone networks and google.com and YouTube Web servers.
the biggest advance for tcp since congestion control was added.
Networks are 100x slower than optimal
In principle, a network can transfer data at nearly the speed of light. Today’s Internet, however, is much slower: our measurements show that latencies are typically more than one, and often more than 2 orders of magnitude larger than the lower bound implied by the speed of light
NTP reimplementation
Interesting account on the reimplementation of NTP (network time protocol, what is responsible for accurate time on all your devices)
2022-11-12: And now it’s time for PTP
Where NTP allows for precision within milliseconds, PTP allows for precision within nanoseconds. PTP has the potential to enable synchronization of GPUs across data centers, which could open up unprecedented scale in AI capabilities that is difficult to achieve today. This level of accuracy will help ensure synchronization of not only the computers on our networks today but also the advanced systems that will be on our networks in the future.
Gregor J. Rothfuss 