From: J.P. Trosclair (jptrosclairjudelawfirm.com)
Date: Mon Dec 01 2008 - 09:01:05 CST

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For the past couple of weeks we've been getting a lot of spam from valid
mail accounts on our domain. The spam gets automatically white listed
since it's from our domain. Short of removing our own domain from our
white lists, I'm looking for a way to put an end to this. Our server
already requires smtp auth for relaying. Is it possible to apply the
same idea to local accounts trying to deliver mail back to local
accounts? I.E., if the sender claims to be joeuserourdomain.com and
wants to email joeuser or janedoe on ourdomain.com, require them to
authenticate with the server first. Most of the spam is being forged as
webmaster or postmaster which are both accounts I need to keep intact.

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
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
disable_vrfy_command = yes
html_directory = no
inet_interfaces = all
mail_owner = postfix
mailbox_size_limit = 0
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = judelawfirm.com, mail1.judelawfirm.com, mail1.jude,
localhost, localhost.localdomain, localhost.judelawfirm.com
mydomain = judelawfirm.com
myhostname = mail1.judelawfirm.com
mynetworks = 127.0.0.0/8, 192.168.1.0/24
myorigin = mail1.judelawfirm.com
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.4.5/README_FILES
sample_directory = /usr/share/doc/postfix-2.4.5/samples
sender_bcc_maps = hash:/etc/aliases_bcc
sender_canonical_classes = header_sender
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_tls_note_starttls_offer = yes
smtp_use_tls = yes
smtpd_banner = $myhostname ESMTP
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_helo_required = yes
smtpd_helo_restrictions = reject_invalid_hostname
smtpd_recipient_restrictions = permit_sasl_authenticated
permit_mynetworks reject_unauth_destination
reject_unlisted_recipient reject_non_fqdn_recipient
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
smtpd_sender_restrictions = reject_non_fqdn_sender
reject_unknown_sender_domain
smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem
smtpd_tls_auth_only = no
smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt
smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
unknown_local_recipient_reject_code = 550

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