The Robustness Principle aka Postel’s Law
[TCP implementations should follow a general principle of robustness:] Be conservative in what you do, be liberal in what you accept from others.
Jon Postel (RFC 761)
Jon Postel was a figure of immense importance to the development of the internet. For more than thirty years, he served as editor of the Requests for Comments (RFCs), authored more than 200 RFCs himself, established the Internet Assigned Numbers Authority (IANA)[Internet Assigned Numbers Authority[(IANA)^], and was a founding member of the Internet Society Internet Society[1].
The Robustness Principle was part of the first RFC on the Transmission Control Protocol. Given the highly heterogeneous nature of systems at the time and the early stage of TCP/IP development, implementations differed from one another in detail. It was therefore important for each implementation to be as fault-tolerant as possible, in order to enable the individual systems to interact at all. Each implementation should be as robust as possible in order to cope with errors on the other side, whilst ideally still enabling communication.
This approach can be applied, in its fundamental principle, to almost all areas of IT: always assume that whatever can go wrong will eventually go wrong, and try to deal with it. But try to be as accurate as possible in what you do.
Why should one read manifestos?
Manifestos express the convictions, goals and intentions of their authors. Since authors usually have extensive experience in their field, they provide a good opportunity to engage with new and perhaps different ideas.
They are therefore an opportunity to reflect on one’s own views, regardless of whether one agrees with their point of view or not.