Questions[smtp-auth](server)

I have set up a Postfix server with SMTP AUTH (STARTTLS on port 587). All my users are in the domain "example.org". I want to enforce the sender address to be "logged-in-user@example.org".

I learned that this can be achieved with the main.cf options

smtpd_sender_restrictions = reject_sender_login_mismatch, ...
smtpd_sender_login_maps = hash:/etc/postfix/smtpd_sender_login_maps

with a login_maps file like:

a@example.org a
b@example.org b
c@example.org c
...

(see also Block sender address spoofing with SMPT AUTH), but this would mean I'll have to edit the login_maps file every time I have a new user. I don't need such a flexible mapping: It should always be "logged-in-user@example.org". Is there an easier option?

How to add DKIM feature to the IIS 7.5 - Windows Server 2008

DomainKeys Identified Mail

I have in /etc/postfix/main.cf:

smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination

and SASL seems to be working:

$ testsaslauthd -u yang -p ... -f /var/spool/postfix/var/run/saslauthd/mux -s smtpd
0: OK "Success."

but I'm getting "Relay access denied" when connecting from outside the network (and e.g. localhost still works fine):

$ telnet blah.com 25
auth plain ...
235 2.7.0 Authentication successful
mail from:<yang@blah.com>
250 2.1.0 Ok
rcpt to:<yang@dest.com>
554 5.7.1 <yang@dest.com>: Relay access denied

Logs:

Oct 18 21:10:19 blah postfix/smtpd[13882]: connect from unknown[x.x.x.x]
Oct 18 21:10:19 blah postfix/smtpd[13882]: setting up TLS connection from unknown[x.x.x.x]
Oct 18 21:10:19 blah postfix/smtpd[13882]: Anonymous TLS connection established from unknown[x.x.x.x]: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)
Oct 18 21:10:19 blah postfix/smtpd[13882]: NOQUEUE: reject: RCPT from unknown[x.x.x.x]: 554 5.7.1 <yang@dest.com>: Relay access denied; from=<yang@blah.com> to=<yang@dest.com> proto=ESMTP helo=<[y.y.y.y]>
Oct 18 21:10:19 blah postfix/smtpd[13882]: disconnect from unknown [x.x.x.x]

Been stumped for some time now. Any hints?

My complete configuration follows; it's based on https://help.ubuntu.com/community/Postfix.

/etc/default/saslauthd:

START=yes
PWDIR="/var/spool/postfix/var/run/saslauthd"
PARAMS="-m ${PWDIR}"
PIDFILE="${PWDIR}/saslauthd.pid"
OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd"

/etc/postfix/main.cf:

# See /usr/share/postfix/main.cf.dist for a commented, more complete version


# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtp_tls_loglevel=1
smtp_tls_security_level=may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_tls_cert_file=/etc/ssl/certs/blah.crt
smtpd_tls_key_file=/etc/ssl/private/blah.key
smtpd_tls_loglevel=1
smtpd_tls_security_level=may
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache

smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

myhostname = blah.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = localhost.blah.com, localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all

# From <http://www.postfix.org/VIRTUAL_README.html>

virtual_mailbox_domains = blah.com invalid.invalid
virtual_mailbox_base = /var/mail/blah
virtual_mailbox_maps = hash:/etc/postfix/vmailbox
virtual_alias_maps = hash:/etc/postfix/valiases
virtual_minimum_uid = 100
virtual_uid_maps = static:1001
virtual_gid_maps = static:1001

sender_bcc_maps = hash:/etc/postfix/bccmaps

# DKIM
smtpd_milters = inet:localhost:8891
non_smtpd_milters = inet:localhost:8891

# Enforce SPF
smtpd_recipient_restrictions =
  permit_mynetworks
  reject_unauth_destination
  check_policy_service unix:private/policyd-spf
policyd-spf_time_limit = 3600

/etc/postfix/sasl/smtpd.conf:

pwcheck_method: saslauthd
mech_list: plain login

I currently only allow connections on port 25 from a mail filtering service's IPs.

I have Exim running on an alternate port for SMTP submission. This port needs to allow non-encrypted connections for now so I can't rely on forcing TLS on the port.

I would like to configure Exim to drop non-authenticated SMTP connections on the alternate port to prevent spammers from connecting and sending spam directly to users.

How would I configure this ACL?

Here is the problem: From any IP address not belonging to your mail server:

telnet me.myemailserver.com 25  

helo me.someserver.com
mail from: <yourusername@mydomain.com>
rcpt to: <yourusername@mydomain.com>
data
This is spam.  Buy my stuff.
.

I'm using Postfix. I'm having a problem finding a solution to requiring SMTP-AUTH for email claiming to be from mydomain.com.

Googling around, this guy has identified the same problem (where I cut-n-paste with some modifications) the above example from: http://www.smartertools.com/forums/t/13182.aspx

This link http://marc.info/?l=postfix-users&m=122814832915131&w=2 gets close to a solution but it has a side effect of requiring SMTP-AUTH for mail not from mydomain.com. For mail not claiming to be from mydomain.com, I would do the usual RBL and Spam filtering.

In short, I want to reject mail to local domains (mydomain.com) from outside/unauthenticated clients claiming to be from local domains (mydomain.com).

This is what I tried: I've tried both permit and reject as the default. Here is exact excerpt from my main.cf:

smtpd_recipient_restrictions = reject_unauth_pipelining,
                           permit_sasl_authenticated,
                           check_recipient_access pgsql:/etc/postfix/pgsql-recipient.cf,
                           reject_unauthenticated_sender_login_mismatch,
                           reject_unauth_destination,
                           reject_unlisted_recipient,
                           check_sender_access pgsql:/etc/postfix/pgsql-sender.cf,
                           reject_unlisted_sender,
                           reject_invalid_hostname,
                           reject_non_fqdn_hostname,
                           reject_non_fqdn_sender,
                           reject_non_fqdn_recipient,
                           reject_unknown_sender_domain,
                           reject_unknown_recipient_domain,
                           reject_rbl_client cbl.abuseat.org,
                           reject_rbl_client sbl.spamhaus.org,
                           reject_rbl_client sbl-xbl.spamhaus.org,
                           reject_rbl_client bl.spamcop.net,
                           reject_rbl_client dnsbl.njabl.org,
                           reject_rbl_client blackholes.wirehub.net,
                           reject_rbl_client relays.mail-abuse.org,
                           reject_rbl_client dialups.mail-abuse.org,
                           reject_rbl_client blackholes.mail-abuse.org,
                           reject_rhsbl_sender dsn.rfc-ignorant.org,
                           (reject and permit both tried here)