Aqui está a minha solução para uma configuração de vários domínios.
Este é o meu main.cf para o postfix:
address_verify_map = btree:/var/spool/postfix/data/verify
alias_maps = hash:/etc/aliases
config_directory = /etc/postfix
default_destination_concurrency_limit = 20
default_destination_rate_delay = 60s
default_destination_recipient_limit = 10
inet_interfaces = all
mail_owner = postfix
mydestination = $myhostname, localhost
myhostname = xyz
mynetworks = 127.0.0.0/8 [::1]/128 ip1.xxx.xxx.xxx ip2.xxx.xxx.xxx
myorigin = $myhostname
sender_dependent_default_transport_maps = regexp:/etc/postfix/transport/sender_dependent_default_transport_maps.regexp
smtp_sasl_security_options = noanonymous, noplaintext
smtp_tls_cert_file = /etc/ssl/certs/...
smtp_tls_key_file = /etc/ssl/private/...
smtp_tls_mandatory_ciphers = high
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_use_tls = yes
smtpd_banner = $myhostname ESMTP
smtpd_recipient_restrictions =
permit_mynetworks,
permit_sasl_authenticated,
reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
check_policy_service inet:127.0.0.1:12525,
check_policy_service inet:127.0.0.1:10023,
reject_unverified_recipient,
reject_unauth_destination,
permit
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_type = dovecot
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/ssl/certs/...
smtpd_tls_key_file = /etc/ssl/private/...
smtpd_tls_mandatory_ciphers = high
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
smtpd_tls_received_header = no
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
virtual_mailbox_base = /var/spool/vmail/
virtual_mailbox_domains = proxy:hash:/etc/postfix/virtual/mailbox_domains
virtual_mailbox_maps = proxy:hash:/etc/postfix/virtual/mailbox_maps
virtual_transport = lmtp:unix:private/dovecot-lmtp
E aqui meu master.cf :
submission inet n - - - - smtpd
-o syslog_name=postfix/submission
-o smtpd_tls_security_level=encrypt
-o smtpd_sasl_auth_enable=yes
-o smtpd_reject_unlisted_recipient=no
-o smtpd_recipient_restrictions=
-o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
pickup fifo n - - 60 1 pickup
-o content_filter=smtp:[localhost]:10024
cleanup unix n - - - 0 cleanup
qmgr fifo n - n 300 1 qmgr
tlsmgr unix - - - 1000? 1 tlsmgr
rewrite unix - - - - - trivial-rewrite
bounce unix - - - - 0 bounce
defer unix - - - - 0 bounce
trace unix - - - - 0 bounce
verify unix - - n - 1 verify
flush unix n - - 1000? 0 flush
proxymap unix - - n - - proxymap
proxywrite unix - - n - 1 proxymap
relay unix - - - - - smtp
showq unix n - - - - showq
error unix - - - - - error
retry unix - - - - - error
discard unix - - - - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - - - - lmtp
anvil unix - - - - 1 anvil
scache unix - - - - 1 scache
maildrop unix - n n - - pipe
flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
uucp unix - n n - - pipe
flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
ifmail unix - n n - - pipe
flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp unix - n n - - pipe
flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix - n n - 2 pipe
flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman unix - n n - - pipe
flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py ${nexthop} ${user}
localhost:10025 inet n - n - - smtpd -v
-o content_filter=
-o smtpd_proxy_filter=
-o smtpd_authorized_xforward_hosts=127.0.0.0/8
-o smtpd_client_restrictions=
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o smtpd_data_restrictions=
-o mynetworks=127.0.0.0/8
-o receive_override_options=no_unknown_recipient_checks
myhostname1:smtp inet n - - - - smtpd -v
-o content_filter=
-o smtpd_proxy_filter=localhost:10024
-o myhostname=myhostname1
myhostname1 unix - - n - - smtp
-o smtp_bind_address=ip1.xxx.xxx.xxx
-o smtp_helo_name=myhostname1
-o syslog_name=postfix_myhostname1
myhostname2:smtp inet n - - - - smtpd -v
-o content_filter=
-o smtpd_proxy_filter=localhost:10024
-o myhostname=myhostname2
myhostname2 unix - - n - - smtp
-o smtp_bind_address=ip2.xxx.xxx.xxx
-o smtp_helo_name=myhostname2
-o syslog_name=postfix_myhostname2
O conteúdo do arquivo /etc/postfix/transport/sender_dependent_default_transport_maps.regexp é:
/@domain1\.de$/ myhostname1:
/@domain2\.de$/ myhostname2:
E aqui está o conteúdo do arquivo /etc/postfix/virtual/mailbox_maps :
[email protected] domain.de/[email protected]/
[email protected] domain.de/[email protected]/
....
Espero que isso seja útil para outras pessoas.