First, I submit my postconf -n, made anonymous, but should still be
accurate.
alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
alternate_config_directories = /etc/postfix-alt
anvil_rate_time_unit = 60s
anvil_status_update_time = 600s
biff = no
bounce_queue_lifetime = 4d
bounce_size_limit = 2000
bounce_template_file = /etc/postfix/bounce.cf
canonical_maps = pcre:/etc/postfix/lowercase,hash:/etc/postfix/genericstable
command_directory = /usr/sbin
config_directory = /etc/postfix
content_filter = lmtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
disable_vrfy_command = yes
fast_flush_domains = serv1.example.com, serv2.example.com, serv3.example.com,
serv4.example.com, serv5.example.com, s
erv6.example.com
html_directory = no
in_flow_delay = 5s
inet_interfaces = localhost,myself.example.com
initial_destination_concurrency = 200
invalid_hostname_reject_code = 556
lmtp_sasl_auth_enable = no
lmtp_sasl_security_options =
local_recipient_maps = hash:/etc/postfix/recipient
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
masquerade_domains = !alt.example.com example.com
maximal_backoff_time = 21600s
message_size_limit = 10000000
minimal_backoff_time = 10800s
mydestination = example.com
myhostname = myself.example.com
mynetworks = 111.111.0.0/16, 127.0.0.0/8
mynetworks_style = class
newaliases_path = /usr/bin/newaliases.postfix
qmgr_message_active_limit = 20000
queue_directory = /var/spool/postfix
queue_run_delay = 500s
rbl_reply_maps = hash:/etc/postfix/rbl_reply
readme_directory = no
recipient_delimiter = +
relay_domains = example.com
relay_recipient_maps = hash:/etc/postfix/recipient
relocated_maps =
sample_directory = /etc/postfix
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtpd_client_connection_count_limit = 20
smtpd_client_connection_rate_limit = 60
smtpd_client_event_limit_exceptions = $mynetworks
smtpd_client_message_rate_limit = 60
smtpd_client_restrictions = reject_unlisted_recipient, check_client_access
cidr:/etc/postfix/client.cidr, check_sender_access
hash:/etc/postfix/whitelist, check_recipient_access
hash:/etc/postfix/recipient_access, check_client_access
hash:/etc/postfix/access, reject_invalid_hostname,
reject_unknown_reverse_client_hostname
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_error_sleep_time = 10s
smtpd_helo_required = yes
smtpd_helo_restrictions = check_helo_access hash:/etc/postfix/helo_access,
reject_invalid_hostname
smtpd_recipient_restrictions = reject_unknown_recipient_domain,
reject_unauth_destination, check_policy_service inet:127.0.0.1:2501,
reject_unknown_sender_domain, reject_non_fqdn_recipient,
reject_non_fqdn_sender, reject_invalid_hostname, check_recipient_access
hash:/etc/postfix/serv3_overquota, check_recipient_access
hash:/etc/postfix/recipient_access, check_sender_access
hash:/etc/postfix/whitelist, check_client_access hash:/etc/postfix/access,
reject_rbl_client PRIVATEKEYREMOVED.r.mail-abuse.com, reject_rbl_client
zen.spamhaus.org, permit
smtpd_sasl_auth_enable = no
smtpd_sender_restrictions = check_sender_access hash:/etc/postfix/blacklist,
check_sender_access hash:/etc/postfix/whitelist, check_client_access
hash:/etc/postfix/access, reject_unknown_sender_domain,
reject_non_fqdn_sender
smtpd_timeout = 60s
transport_maps = hash:/etc/postfix/transport
unknown_address_reject_code = 550
unknown_client_reject_code = 555
unknown_local_recipient_reject_code = 550
unverified_recipient_reject_code = 550
unverified_sender_reject_code = 550
virtual_alias_maps = hash:/etc/postfix/relocated
hash:/etc/postfix/class_lists hash:/etc/postfix/virtual
My server will properly not queue email for most addresses sent to bogus
addresses.
Aug 30 22:30:20 myself postfix/smtpd[25013]: NOQUEUE: reject: RCPT from
mta03.anisp.ca[24.111.111.111]: 550 5.1.1 <12345...@example.com>: Recipient
address rejected: User unknown in local recipient table
However, if the email address is of the format of 6 numbers followed by a
letter, then the message is
queued and bounced.
Aug 30 22:30:03 myself postfix/local[25084]: 9E79419CF2D: to=<
1234...@example.com>, relay=local, delay=0.26, delays=0.13/0.07/0/0.05,
dsn=5.1.1, status=bounced (unknown user: "123456t")
The pattern of six digits and one letter is significant to how common email
addresses are set up at our institution.
The canonical_maps entry pointing to lowercase is related to this.
lowercase contains:
/^([0-9]{6}[a...@example.com)$/ $1
It seems the message was queued somehow as a result of this. Is there a
suggested workaround
to avoid unknown users from being queued?
I'm not sure why this was set up by a predecessor. It doesn't seem to do
anything in my read of it,
although it might be taking advantage of a canonical maps feature related to
lowercase.
--Donald
