ifelse(SECTION, `MAIN', `dnl
helo_allow_chars = _
')
dnl
ifelse(SECTION, `ACL_CHECK_RCPT', `dnl
dnl
ifelse(confCHECK_HELO_UNDERSCORE, `REJECT', `dnl
	# 5xx в случае использования "_" в HELO
	deny	! authenticated	= *
		! hosts		= +relay_from_hosts
		condition	= ${if match{$sender_helo_name}{\N^.*_\N}{yes}{no}}
		message		= Connection rejected. \
				Underscores in HELO are not permitted by RFC2821.\n\
				Fix your broken mail server and try again.
		log_message	= Underscore has been found in HELO
')
dnl
	# Warning в случае использования "_" в HELO
	warn	condition	= ${if match{$sender_helo_name}{\N^.*_\N}{yes}{no}}
		message		= X-Warn-HELO-Underscore: Underscore has been found in HELO
		log_message	= Underscore has been found in HELO
')