Sorry for inception. How can I configure postfix to cause an instant message returned, rather than 4xx code to make peer MTA retry many times?
Thanks November 16, 2022, 8:09 AM, "raf" <post...@raf.org> wrote: > > On Mon, Nov 14, 2022 at 12:33:02PM -0700, Bryan Arenal <b.are...@gmail.com> > wrote: > > > > > Hi there, > > > > Is Postfix capable of checking DKIM and SPF records on incoming email > > and adding headers based upon its findings? For example, an email > > with a valid DKIM signature shows these headers sent to O365: > > > > ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass > > smtp.mailfrom=example.com; dmarc=pass action=none header.from=example.com; > > dkim=pass header.d=example.com; arc=none > > > > My google searches have only returned results on how to do DKIM > > signing on outbound email and not how to verify them on inbound > > emails. > > > > Thanks! > > > > That "ARC-Authentication-Results" header is actually > ARC, not DKIM/SPF (i.e. a meta-DMARC for forwarders > that modify what is being forwarded). I don't know what > can create those headers. OpenARC seems defunct. I > think OpenDMARC checks ARC headers (as well as > DMARC/DKIM/SPF) and adds "Authentication-Results" > headers. > > rspamd probably does it as well. > > There's a tutorial on adding OpenDMARC to postfix on Debian here: > > https://www.linuxbabe.com/mail-server/opendmarc-postfix-debian > > It's for debian but there might be equivalent tutorials > for other Linux systems on that website. > > It might assume other steps in the complete tutorial: > > > https://www.linuxbabe.com/mail-server/build-email-server-from-scratch-debian-postfix-smtp > > But maybe not. > > People say good things about rspamd as well. Check that out. > > cheers, > raf >
