Let’s look on DNS message diagram to get some idea about way to make query (thanks to authors of this image): The next step is to try to tell the DNS server what we specifically want from it. It is well known that DNS is one of the few protocols that uses the UDP protocol and we have already prepared a UDP client that establishes a connection to a remote host on which a recursive DNS resolver is expected to listen on port 53. We made sure that there is no implementation of the DNS protocol for our programming language, and we began to implement our own client. I’m sure that my list of good libraries is incomplete, but that doesn’t mean they don’t exist. Almost all DNS client implementations present in the standard libraries of programming languages are oversimplified and have poor interfaces that hide many important details.
I must say right away that the number of good libraries for working with DNS is very small, I can only recommend MiekG DNS, although it is also not suitable as a client library. Let’s follow the process of developing DNS client from scratch to highlight most obvious implementation issues you may experience. If you need to publish some configuration for your clients or you’re looking for best protocol for service discovery then please do not use DNS. Please do not use DNS protocol for your applicationįor more than 4 years I have been working exclusively with the DNS protocol and during this time I have collected a fairly large number of ways to shoot myself in the foot in a seemingly empty place.ĭNS is great for the task of bringing visitors to your site or API endpoint, but that’s where use of DNS protocol in your application should end.
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