On Tue 24/Nov/2020 18:03:51 +0100 John Levine wrote:
In article <efa0117e-5b17-800d-820d-b5d2413c6...@tana.it> you write:
One of the points of the tree walk is to get rid of the PSL processing.
The PSL processing is a local lookup on an in-memory suffix tree. How is it a
progress to replace it with a tree walk? A PSL search is lightning faster than
even a single DNS lookup, isn't it?
You have to download a copy of the PSL, read it into your program, and
parse it into some internal form. The PSL is over 200K of text and
13,000 lines, so while it's not a large file, it's not zero either.
Right. The optimal solution would be to load the list and the lookup algorithm
as a shared object. Currently, my filter has its private copy of it. But then
I don't reload the filter so often that parsing the file is noticeable. To
wit, loading the virus database takes much much longer.
If you're lucky you can amortize your PSL parsing across multiple
DMARC checks, but your DNS cache amortizes DNS lookups across multiple
checks, too.
I doubt I'd get comparable efficiency, even if my mail server has a dedicated
caching resolver. Mail servers that rely on stub resolvers would experience a
noticeable degradation.
The DNS approach has the advantage that you don't have to depend on a
third party's text file updated at unknown intervals,
Agreed.
and also makes it easier to deal with what I've called the Holy Roman Empire
problem.
Uh? The Holy Roman Empire became a disconnected tree soon after Charlemagne's
death, so that looks like some of the dystopic scenarios that ISOC conceived a
few years ago. Not sure what you mean.
Best
Ale
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