Policy at Internet scale is a little understood, and difficult (potentially impossible) to solve problem. Joel Halpern joins the History of Networking over at the Network Collective to talk about the history of policy in the Internet at large, and networked systems in general.
Two ideas that are widespread, and need to be addressed—
First, there is no enterprise, there are no service providers. There are problems, and there are solutions.
When I was young (and even more foolish than I am now) I worked for a big vendor. When this big vendor split the enterprise and service provider teams, I thought this kindof made sense. After all, providers have completely different requirements, and should therefore run with completely different technologies, equipment, and software. When I thought of providers in those days, I thought of big transit network operators, like AT&T, and Verizon, and Orange, and Level3, and Worldcom, and… The world has changed since then, but our desire to split the world into two neat halves has not.
If you want to split the world into two halves, split it this way: There are companies who consider the network an asset, and companies that consider the network a Continue reading
He got the idea while analyzing the Vawtrak malware after discovering that it read multiple fields in the X.509 certificate provided by the server before proceeding. Jason initially thought these fields were used as a C2 channel, but then realized that Vawtrak performed a Continue reading
Considering the DNS query chain—
banana.example
banana.example
does not existThere are two possible responses in this chain of queries, actually. .example
might not exist at all. In this case, the root server will return a server not found
error. On the other hand, .example
might exist, but banana.example
might not exist; in this case, the authoritative server is going to return an NXDOMAIN
record indicating the subdomain does not exist.
Assume another hosts, a few moments later, also queries for banana.example.
Should the recursive server request the same information all over again for this second query? It will unless it caches the failure of the first query—this is the negative cache. This negative cache reduces load on the overall system, but it can also be considered a bug.
Take, for instance, the case where you set up a new server, assign it banana.example, jump to a host and try to connect to the new server before the new DNS information has been propagated through the system. On Continue reading