There is sendmail relay host for LAN/external users using AUTH or trusting local users, but there is a problem that sendmail accepts mail from trusted users addressed for non existing domains (non intentionally), like gmai@.cm which are written by mistake.
Flow is this: Auth user -> sendmail -> relay mail server
of course mail gets back from relay server with error that recipient domain does not exist, but I want to intercept this situation at sendmail with smart host.
sendmail config has important parameters:
dnl SMTP Auth define(`confAUTH_OPTIONS',`A y') include(`/etc/mail/sasl/sasl.m4')dnl FEATURE(`no_default_msa')dnl DAEMON_OPTIONS(`Family=inet, Name=MTA-v4, Port=smtp, Addr=0.0.0.0')dnl DAEMON_OPTIONS(`Family=inet, Name=MSP-v4, Port=submission, Addr=0.0.0.0')dnl define(`confPRIVACY_FLAGS',dnl `needmailhelo,needexpnhelo,needvrfyhelo,restrictqrun,restrictexpand,nobodyreturn,authwarnings,noreceipts')dnl FEATURE(`access_db')dnl FEATURE(`use_cw_file')dnl FEATURE(`always_add_domain')dnl FEATURE(`virtusertable')dnl define(`SMART_HOST',`smarthost.mydom.com')dnl define(`conf_LOG_Level',`14')dnl dnl # antispam FEATURE(`dnsbl',`.... MAILER_DEFINITIONS MAILER(`local')dnl MAILER(`smtp')dnl
and it's important to mention, there is mimedefang filter with antivirus and spam-assasin.
How I can force sendmail to not relay bad recipient domain?