poolpOrg
commented
3 years ago I had not seen your issue.
I didn't run into this because I always setup a local resolver acting as a local cache but indeed I should swap net.LookupIP() with a resolver.LookupIP as it takes a context and I can pass a timeout there.
I'll have a look at it as time allows and will publish a new release when it's fixed.
if senderscore is not answering correctly or running into timeout, endless smtp sessions will be opened (at new incoming messages), but no mail processing is happening. when the filter is running on the connection level, then the messages are neither delivered nor queued, because it "hangs" on the filter processing. Is there a possibility for a timeout? When senderscore request fails (maybe retry 2-3 times) and then pass the message (even if not scanned by the filter). On large mx this will be a serious problem, when senderscore is not working, because after 1-2min the "SMTP client limit is reached" and the server isn't responding to SMTP anymore, and there will be a "message jam" after the filter is working again (or not). Maybe senderscore is also rate-limiting, but that's not documented neither at this plugin's readme nor at senderscore itself.