https://news.ycombinator.com/item?id=37127604<p>...didn't get any, but I found some via an unfortunate client, who was doing this via a CRM without setting any sort of domain authentication up for their sender (I do data migrations at my day job, so I see everyone's skeletons...)<p>tl;dr: bounce rate will be about 45-50% over time if you don't set up any sort of DKIM or SPF records, varying slightly depending on your recipients, but it's the <i>IMPORTANT PEOPLE</i> you can't email.<p>Excerpt below, <-- email domain sent to, --> email server which rejected the message.<p>Email Bounced | Email Server<p>---------------------------------------<p>@cbmove.com usb-smtp-inbound-1.mimecast.com.<p>@pattonboggs.com eu-smtp-inbound-1.mimecast.com.<p>@montgomerycollege.edu mx0a-0016b401.pphosted.com.<p>@iri.org us-smtp-inbound-1.mimecast.com.<p>@stemedcoalition.org us-smtp-inbound-2.mimecast.com.<p>@bipc.com us-smtp-inbound-1.mimecast.com.<p>@dickblick.com us-smtp-inbound-1.mimecast.com.<p>@student.american.edu mx0a-00240c01.pphosted.com.<p>@cbf.org us-smtp-inbound-1.mimecast.com.<p>@binghamt.gannett.com us-smtp-inbound-1.mimecast.com.<p>@hhlaw.com eu-smtp-inbound-2.mimecast.com.<p>@pattonboggs.com eu-smtp-inbound-1.mimecast.com.<p>@iri.org us-smtp-inbound-1.mimecast.com.<p>@tmgcustommedia.com us-smtp-inbound-1.mimecast.com.<p>@washington.goethe.org mx02.goethe.de.<p>@nbcuni.com mxb-00176a04.gslb.pphosted.com.<p>@jonesday.com mxb-00393202.gslb.pphosted.com.<p>@intelsatgeneral.com mxb-0056a401.gslb.pphosted.com.<p>@qga.com mxa-00173601.gslb.pphosted.com.<p>@wpost.com mxb-001a3c01.gslb.pphosted.com.<p>@nbcuni.com mx0a-00176a04.pphosted.com.<p>@tr.com mxb-00160c04.gslb.pphosted.com.<p>@arts.ri.gov mx0b-00137801.pphosted.com.<p>@readexpress.com mxa-001a3c01.gslb.pphosted.com.<p>@icloud.com mx02.mail.icloud.com.<p>@readexpress.com mxa-001a3c01.gslb.pphosted.com.<p>@nbc.com mxa-00176a04.gslb.pphosted.com.<p>@wellsfargoadvisors.com mxa-00004003.gslb.pphosted.com.<p>@american.edu mx0b-00240c01.pphosted.com.<p>@chron.com mxa-0018d701.gslb.pphosted.com.<p>@na.ko.com mxa-0037a502.gslb.pphosted.com.<p>@bbandt.com mxb-0058fb01.gslb.pphosted.com.<p>@exxonmobil.com mxa-00016305.gslb.pphosted.com.<p>@dcist.com mx0a-00240c01.pphosted.com.<p>@k12.com mxa-00678201.gslb.pphosted.com.<p>@stanford.edu mxb-00000d07.gslb.pphosted.com.<p>@ge.com mx0a-00176a02.pphosted.com.<p>@american.edu mx0b-00240c01.pphosted.com.<p>@dynetics.com mxa-00336402.gslb.gpphosted.com.<p>@washpost.com mxa-001a3c01.gslb.pphosted.com.<p>@pnc.com mxb-000ade01.gslb.pphosted.com.<p>@vh1staff.com mxa-00262c01.gslb.pphosted.com.<p>@hosthotels.com mxa-00320801.gslb.pphosted.com.<p>@dc.gov dc-gov.mail.protection.outlook.com.<p>@dc.gov dc-gov.mail.protection.outlook.com.<p>@arenastage.org arenastage-org.mail.protection.outlook.com.