Mail to localhost gets delivered but mail to FQDN bounces “mail for localhost loops back to myself”

My issue is that (on the mail server, which is named `mail-test`) I can do

Code:

echo "test!" | sendmail ethan@localhost

but I can't do

Code:

echo "test!" | sendmail ethan@mail-test.[REDACTED DOMAIN]

.

Those messages bounce - here are the two log lines showing that:

Code:

    Apr 10 23:35:41 mail-test postfix/qmgr[26638]: DA423600A6B: from=<root@mail-test.[REDACTED DOMAIN]>, size=300, nrcpt=1 (queue active)
    Apr 10 23:35:41 mail-test postfix/smtp[26644]: DA423600A6B: to=<ethan@mail-test.[REDACTED DOMAIN]>, relay=none, delay=0.95, delays=0.95/0/0/0, dsn=5.4.6, status=bounced (mail for localhost loops back to myself)

The FQDN is in `mydestination` in `main.cf` and this is the same behavior if the options for Amavis are present in the config file or not. What can I do to fix this? Thank you!

---

main.cf:

Code:

    soft_bounce = no
    queue_directory = /var/spool/postfix
    command_directory = /usr/sbin
    daemon_directory = /usr/lib/postfix/sbin
    data_directory = /var/lib/postfix
    mail_owner = postfix
    myhostname = mail-test.[REDACTED DOMAIN]
    mydomain = [REDACTED DOMAIN]
    myorigin = $mydomain
    inet_interfaces = all
    mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
    unknown_local_recipient_reject_code = 550
    mynetworks = 127.0.0.0/8, [REDACTED]
    transport_maps = hash:/etc/postfix/transport
    alias_maps = hash:/etc/aliases
    alias_database = hash:/etc/aliases
    recipient_delimiter = +
    mailbox_command = /usr/lib/dovecot/deliver -d "$USER" -f "$SENDER"
    smtpd_banner = $myhostname ESMTP $mail_name (GNU/Linux)
    default_destination_concurrency_limit = 60
    default_extra_recipient_limit = 20
    debug_peer_level = 2
    debugger_command =
        PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
        ddd $daemon_directory/$process_name $process_id & sleep 5
    sendmail_path = /usr/sbin/sendmail
    newaliases_path = /usr/bin/newaliases
    mailq_path = /usr/bin/mailq
    setgid_group = postdrop
    html_directory = no
    manpage_directory = /usr/share/man
    sample_directory = /etc/postfix
    readme_directory = no
    inet_protocols = all
    smtpd_use_tls = yes
    smtpd_tls_key_file = /etc/postfix/ssl/key
    smtpd_tls_cert_file = /etc/postfix/ssl/cert
    smtpd_tls_CAfile = /etc/postfix/ssl/ca
    smtpd_tls_mandatory_ciphers = high
    smtpd_tls_mandatory_exclude_ciphers = aNULL, MD5
    smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
    smtpd_tls_loglevel = 1
    smtpd_tls_received_header = yes
    smtpd_tls_session_cache_timeout = 3600s
    smtp_tls_security_level = may
    smtpd_sasl_auth_enable = yes
    broken_sasl_auth_clients = yes
    smtpd_tls_auth_only = yes
    smtpd_sasl_security_options = noanonymous
    smtpd_sasl_type = dovecot
    smtpd_sasl_path = private/auth
    smtpd_helo_required = yes
    smtpd_helo_restrictions = reject_invalid_helo_hostname
    strict_rfc821_envelopes = yes
    smtpd_client_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_rbl_client zen.spamhaus.org, reject_unauth_pipelining
    smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_pipelining,
        check_sender_access hash:/etc/postfix/sender_access
    smtpd_data_restrictions = reject_unauth_pipelining
    smtpd_recipient_restrictions = reject_invalid_hostname, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, check_recipient_access hash:/etc/postfix/recipient_access, check_client_access hash:/etc/postfix/client_access
    amavis_destination_concurrency_limit = 50
    default_process_limit = 70
    smtp_mx_session_limit = 100
    smtp_destination_concurrency_limit = 100
    authorized_submit_users = ![REDACTED], static:all

master.cf:

Code:

    smtp      inet  n       -       y       -       -       smtpd
        -o content_filter=amavisfeed:[127.0.0.1]:10024
    submission inet n       -       y       -       -       smtpd
        -o content_filter=amavisfeed:[127.0.0.1]:10024
    smtps     inet  n       -       y       -       -       smtpd
    pickup    unix  n       -       y       60      1       pickup
             -o content_filter=
             -o receive_override_options=no_header_body_checks
    cleanup   unix  n       -       y       -       0       cleanup
    qmgr      unix  n       -       n       300     1       qmgr
    tlsmgr    unix  -       -       y       1000?   1       tlsmgr
    rewrite   unix  -       -       y       -       -       trivial-rewrite
    bounce    unix  -       -       y       -       0       bounce
    defer     unix  -       -       y       -       0       bounce
    trace     unix  -       -       y       -       0       bounce
    verify    unix  -       -       y       -       1       verify
    flush     unix  n       -       y       1000?   0       flush
    proxymap  unix  -       -       n       -       -       proxymap
    proxywrite unix -       -       n       -       1       proxymap
    smtp      unix  -       -       y       -       -       smtp
    relay     unix  -       -       y       -       -       smtp
    showq     unix  n       -       y       -       -       showq
    error     unix  -       -       y       -       -       error
    retry     unix  -       -       y       -       -       error
    discard   unix  -       -       y       -       -       discard
    local     unix  -       n       n       -       -       local
    virtual   unix  -       n       n       -       -       virtual
    lmtp      unix  -       -       y       -       -       lmtp
    anvil     unix  -       -       y       -       1       anvil
    scache    unix  -       -       y       -       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}
    amavisfeed      unix  -    -       n       -       2       smtp
     -o smtp_data_done_timeout=1200
     -o smtp_send_xforward_command=yes
     -o disable_dns_lookups=yes
     -o max_use=20
    127.0.0.1:10025 inet n  -       y       -       -       smtpd
     -o content_filter=
     -o smtpd_delay_reject=no
     -o smtpd_client_restrictions=permit_mynetworks,reject
     -o smtpd_helo_restrictions=
     -o smtpd_sender_restrictions=
     -o smtpd_recipient_restrictions=permit_mynetworks,reject
     -o smtpd_data_restrictions=reject_unauth_pipelining
     -o smtpd_end_of_data_restrictions=
     -o smtpd_restrictions_classes=
     -o mynetworks=127.0.0.0/8
     -o smtpd_error_sleep_time=0
     -o smtpd_soft_error_limit=1001 
     -o smtpd_hard_error_limit=1000
     -o smtpd_client_connection_count_limit=0
     -o smtpd_client_connection_rate_limit=0
     -o receive_override_options=no_header_body_checks,no_unknown_recipient_checks,no_milters
     -o local_header_rewrite_clients=

Amavis configuration is all default settings. I am on Ubuntu 18.04 LTS.

 

Depends if you want to use virtual domains. If yes, use:
myhostname = server.domain.com
myorigin = domain.com
mydestination = localhost

If you need later:
virtual_alias_domains = domain.com sub.domain.com

Make sure you have set /etc/mailname correctly

Read: http://www.postfix.org/postconf.5.html#mydestination
If you want to use virtual domains: http://www.postfix.org/VIRTUAL_README.html

 

I'm not using virtual domains, for now at least. I am sending to `mail-test.domain.com` and `mail-test` is the hostname of the server.

 

OK, then your configuration should be fine (?)
http://www.postfix.org/BASIC_CONFIGURATION_README.html

myhostname = mail-test.[REDACTED DOMAIN]
mydomain = [REDACTED DOMAIN]
myorigin = $mydomain
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

With that, mail is sent with user@$mydomain and received for $mydomain and $myhostname and localhost
I do not know, why you get this error. Is it correct, that you get the error about "localhost" when sending to "mail-test.domain.com"? Then it looks like the problem could be a content filter. Do you get moe information from the debug log? http://www.postfix.org/DEBUG_README.html