postconf -n :

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
header_checks = pcre:/etc/postfix/header_checks
html_directory = no
inet_interfaces = localhost, 91.123.234.123
inet_protocols = all
mailbox_transport = lmtp:unix:private/dovecot-lmtp
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname = $HOST.$DOMAIN
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
unknown_local_recipient_reject_code = 550
virtual_alias_maps = ldap:/etc/postfix/ldap-virtual-accountmaps.cf, ldap:/etc/postfix/ldap-virtual-alias-maps.cf
virtual_mailbox_domains = ldap:/etc/postfix/ldap-virtual-mailbox-domains.cf
virtual_mailbox_maps = ldap:/etc/postfix/ldap-virtual-mailbox-maps.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp


dovecot -n:
# 2.0.9: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.32-131.17.1.el6.x86_64 x86_64 CentOS Linux release 6.0 (Final) 
auth_debug = yes
auth_debug_passwords = yes
auth_verbose = yes
debug_log_path = /var/log/dovecot/dovecot_debug.log
disable_plaintext_auth = no
first_valid_uid = 5000
info_log_path = /var/log/dovecot/dovecot_info.log
last_valid_uid = 5000
lda_mailbox_autocreate = yes
mail_debug = yes
mail_gid = vmail
mail_location = maildir:~/Maildir
mail_uid = vmail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date
mbox_write_locks = fcntl
passdb {
  args = /etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
plugin {
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
protocols = imap lmtp
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
  unix_listener auth-userdb {
    group = vmail
    mode = 0600
    user = vmail
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0660
    user = postfix
  }
}
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
userdb {
  args = /etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
protocol lmtp {
  mail_plugins = 
}
protocol lda {
  log_path = /var/log/dovecot/dovecot-deliver.log
  mail_plugins = 
  postmaster_address = postmaster@my-domain.com
}


maillog error:
Oct 17 18:22:26 rps2 postfix/lmtp[9207]: 6F7E2E23BC: to=<henning@my-domain.com>, relay=none, delay=4552, delays=4552/0.03/0/0, dsn=4.4.1, status=deferred (connect to rps2.my-domain.com[private/dovecot-lmtp]: Permission denied)