Can you describe in more detail what line_length_limit does? I guess part of my question here is I don’t understand it’s purpose and thus why it doesn’t/couldn’t apply here.
> On Sep 16, 2021, at 05:06, Wietse Venema <wie...@porcupine.org> wrote: > > Matt Corallo: >> When debugging a DKIM signature failure, I found that: >> >> * Thunderbird doesn't care at all about the SMTP line length limit, happily >> sending longer lines >> when you quote a 1000-charachter line, >> * Postfix happily accepts the too-long-line, passing it as-is to opendkim >> * opendkim is unmaintained and doesn't care either, signing the too-long >> line, >> * Postfix (and other MTAs downstream too, probably) will truncate the line >> as documented, breaking >> the DKIM signature. > > Indeed, Thunderbird sends SMTP mail that violates the SMTP spec, > and that is the real problem. The Postfix SMTP client breaks long > lines for SMTP protocol compliance, but other Postfix delivery > agents do not (because they aren't bound by the rules of SMTP). > > I'm sure that the DKIM spec has guidelines for how to make signature > breakage less likely, including a recommendation to avoid sending > send non-compliant messages. > > Wietse
