Hello, I am trying to setup replication between two Mac OS X El Capitan Server. I have added the field as I could understand from the replication page of dovecot and from a few poste in the mailing list. The mac uses the system user _dovecot as main system account. I have setup ssh keys between the two systems for the two _dovecot servers. SSh works fine from the terminal. But yet, I get these messages in the log file : Mar 09 20:18:44 auth: Error: od[getpwnam_ext](submit): No record for user Mar 09 20:18:44 doveadm: Error: Host key verification failed. Mar 09 20:18:44 dsync-local(submit): Error: read(_dovecot at laposte.mycompagny.com) failed: EOF Mar 09 20:18:44 dsync-local(submit): Error: Remote command returned error 255 Mar 09 20:23:44 auth: Error: od[getpwnam_ext](submit): No record for user Mar 09 20:23:44 doveadm: Error: Host key verification failed. Mar 09 20:23:44 dsync-local(submit): Error: read(_dovecot at laposte.mycompagny.com) failed: EOF Mar 09 20:23:44 dsync-local(submit): Error: Remote command returned error 255 and so on every few minutes. I have a few things about which I am not sure. We configure port 12345, but nothing listen on that port. The doveadm_password, what is it exactly ? Should I use a distinct account than _dovecot for synchronisation (all the fields that need to be added for replication) ? Here is my configuration, any help would be appreciated : # 2.2.5: /Library/Server/Mail/Config/dovecot/dovecot.conf # OS: Darwin 15.3.0 x86_64 hfs auth_mechanisms = cram-md5 digest-md5 gssapi auth_realms = labanque.mycompagny.com auth_socket_path = /var/run/dovecot/auth-userdb auth_username_format = %n debug_log_path = /Library/Logs/Mail/mail-debug.log default_internal_user = _dovecot default_login_user = _dovenull doveadm_password = MyOwnSecret doveadm_port = 12345 dsync_remote_cmd = ssh -l%{login} %{host} doveadm dsync-server -u%u first_valid_gid = 6 first_valid_uid = 6 imap_id_log = * imap_id_send = "name" * "version" * imap_urlauth_submit_user = submit info_log_path = /Library/Logs/Mail/mail-info.log log_path = /Library/Logs/Mail/mail-err.log login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e %c mail_access_groups = mail mail_attribute_dict = file:/Library/Server/Mail/Data/attributes/attributes.dict mail_location = maildir:/Library/Server/Mail/Data/mail/%u mail_log_prefix = "%s(pid %p user %u): " mail_plugins = quota zlib acl fts fts_sk notify replication 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 ihave mdbox_rotate_size = 200 M namespace acl-mailboxes { list = children location = maildir:/Library/Server/Mail/Data/mail/users/%%u:INDEX=/Library/Server/Mail/Data/mail/shared/%%u prefix = shared.%%u. separator = . subscriptions = no type = shared } namespace inbox { inbox = yes location mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix } namespace list-archives { list = children location = maildir:/Library/Server/Mail/Data/listserver/messages/archive/lists/%%u:INDEX=/Library/Server/Mail/Data/listserver/messages/archive/shared/%%u prefix = archives.%%u. separator = . subscriptions = no type = shared } passdb { driver = od } passdb { args = /Library/Server/Mail/Config/dovecot/submit.passdb driver = passwd-file } plugin { acl = vfile:/Library/Server/Mail/Config/dovecot/global-acls:cache_secs=300 acl_shared_dict = file:/Library/Server/Mail/Data/shared/shared-mailboxes fts = sk mail_replica = remote:_dovecot at laposte.mycompagny.com quota = maildir:User quota quota_warning = storage=100%% quota-exceeded %u quota_warning2 = storage=80%% quota-warning %u sieve = /Library/Server/Mail/Data/rules/%u/dovecot.sieve sieve_dir = /Library/Server/Mail/Data/rules/%u stats_refresh = 30 secs stats_track_cmds = yes } postmaster_address = postmaster at labanque.mycompagny.com protocols = imap lmtp sieve pop3 quota_full_tempfail = yes service aggregator { fifo_listener replication-notify-fifo { user = _dovecot } unix_listener replication-notify { user = _dovecot } } service auth { extra_groups = _keytabusers idle_kill = 15 mins unix_listener auth-userdb { user = _dovecot } } service dns_client { unix_listener dns-client { mode = 0600 } } service doveadm { user = _dovecot } service imap-login { inet_listener imap { port = 143 } inet_listener imaps { port = 993 ssl = yes } service_count = 0 } service imap { client_limit = 5 process_limit = 200 service_count = 0 } service indexer-worker { user = _dovecot } service lmtp { unix_listener lmtp { mode = 0600 } } service managesieve-login { inet_listener sieve { port = 4190 } } service pop3-login { inet_listener pop3 { port = 110 } inet_listener pop3s { port = 995 ssl = yes } } service pop3 { client_limit = 5 process_limit = 200 service_count = 0 } service quota-exceeded { executable = script /Applications/Server.app/Contents/ServerRoot/usr/libexec/dovecot/quota-exceeded.sh unix_listener quota-exceeded { group = mail mode = 0660 user = _dovecot } user = _dovecot } service quota-warning { executable = script /Applications/Server.app/Contents/ServerRoot/usr/libexec/dovecot/quota-warning.sh unix_listener quota-warning { group = mail mode = 0660 user = _dovecot } user = _dovecot } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { mode = 0600 } } service stats { fifo_listener stats-mail { mode = 0600 user = _dovecot } } ssl = required ssl_ca = </etc/certificates/labanque.mycompagny.com.423929C9712FE705D69805A43769B318C7D3CBB3.chain.pem ssl_cert = </etc/certificates/labanque.mycompagny.com.423929C9712FE705D69805A43769B318C7D3CBB3.cert.pem ssl_cipher_list = ALL:!LOW:!SSLv2:!EXP:!aNULL:!ADH:!eNULL ssl_key = </etc/certificates/labanque.mycompagny.com.423929C9712FE705D69805A43769B318C7D3CBB3.key.pem ssl_key_path = /etc/certificates/labanque.mycompagny.com.423929C9712FE705D69805A43769B318C7D3CBB3.key.pem userdb { args = partition=/Library/Server/Mail/Config/dovecot/partition_map.conf global_quota=5000 enforce_quotas=yes driver = od } userdb { args = /Library/Server/Mail/Config/dovecot/submit.passdb driver = passwd-file } verbose_proctitle = yes protocol lmtp { mail_plugins = quota zlib acl fts fts_sk sieve } protocol lda { mail_plugins = quota zlib acl fts fts_sk sieve } protocol imap { mail_max_userip_connections = 20 mail_plugins = quota zlib acl fts fts_sk imap_acl imap_quota imap_zlib } protocol pop3 { mail_max_userip_connections = 6 }