Am 19.04.2020 um 18:28 schrieb S.Bob: > > I installed sendmail via yum, but if I test it like this: > > > echo "Subject: sendmail test" | sendmail sbob at quadratum-braccas.com > > > I get a local mail on the server with this every time: [ ... ] Hi, your provided sendmail.mc shows that you have done zero customization. So please let me ask: do you have experience to setup and operate an MTA and especially Sendmail? I am asking because that's not trivial and as you cannot judge about the error you are getting implies that you lack essential information. It is ok not to know how to run an MTA, but then you shouldn't. At least you should configure Sendmail as a null-client. Do as Jason wrote and configure the SMART_HOST of your ISP. Take care for proper `' as those appear wrong in Jason's post. And make sure that the sendmail-cf package is installed so that the sendmail.cf can be rebuild after sendmail.mc customizations. Alexander