Theo Van Dinter wrote:
I'm not saying anything positive or negative about the different lists, but there's a long precedent of doing this type of thing w/ bits in a standard DNS response. Look at SURBL and URIBL, for example -- a single response encodes multiple individual list entries, and there's no special code that needs to be written for it.
Yes - using bits has been traditional and it has worked well in the past where mostly it was used to indicate if something is or is not blacklisted. What I'm proposing envisions returning a wide variety of information and where host names might be in multiple categories. Using numbers is also confused when it is possible that multiple numbers could be returned and then standardizing on what bits mean what messages.
Returning a single string allows for human readable messages as flags. You make one call to get the string and then parse the string for the flags you are looking for. Generally bit based systems require complex bit masking that, except for SA and Exim, bost systems aren't capable of dealing with. In my case I've been returning different codes for a wide variety of listing and I'm about to add more and I'm wondering, do I stay with bits or do I ask id bits are the right path to the future.
For example. A host is verified as yahoo.com. On my system it is yellow listed. That means that not information can be decided based on the IP address as to is it is spam or ham. It is also a flag that indicates not to either white list or black list the IP. But now I want to also list it as a freemail domain because I do conditional based on if it is freemail. So I'm now returning 2 pieces of information about that host.
Suppose I want to return 3 or 4 or more flags on the host name? Do I return 4 values? Or do I return one value and use bitmasks? Or - as I'm suggesting here - do I return a string with all the flags I want? I'm thinking the in the long term that there are going to be a lot of flags that will be useful to classify the host and that a string is ultimately the best solution.
I'm at a point where the numbers I return are more complex for most systems to handle. Therefore I can switch at this point to a string system because the bit mask system to do what I want doesn't exist either. So I'm thinking maybe I need to do this right from the start and not end up regretting it later. So that's what I'm leaning towards.
