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Manage iRedAPD (white/blacklists, greylisting, throttling and more)

Introduce iRedAPD

iRedAPD is a simple Postfix policy server, written in Python, with plugin support. It listens on 127.0.0.1:7777 by default, and runs as a low-privileged user iredapd.

Source code is hosted on GitHub.

How to disable iRedAPD service

To disable iRedAPD service:

1. please remove all check_policy_service inet:127.0.0.1:7777 in Postfix config file /etc/postfix/main.cf (Linux/OpenBSD) or /usr/local/etc/postfix/main.cf (FreeBSD).
2. Restart or reload Postfix service.
3. Disable iredapd service.

How to enable or disable iRedAPD plugins

iRedAPD plugins are Python files under /opt/iredapd/plugins/ directory. To enable a plugin, please find line plugins = in iRedAPD config file /opt/iredapd/settings.py, for example:

plugins = ['greylisting', 'throttle']

If you want to enable plugin reject_sender_login_mismatch (file /opt/iredapd/plugins/reject_sender_login_mismatch.py), please add the plugin name without extension .py in plugins = like below, then restart iRedAPD service:

plugins = ['greylisting', 'throttle', 'reject_sender_login_mismatch']

The priorities of plugins shipped in iRedAPD are hard-coded, so the order of plugin names doesn't matter.

To disable a plugin, just remove the plugin name and restart iRedAPD service.

How to add custom settings

iRedAPD has some default settings in file /opt/iredapd/libs/default_settings.py, but you should never modify it. Instead, you should copy the settings you want to modify from /opt/iredapd/libs/default_settings.py to /opt/iredapd/settings.py, then update it with new values. This way you will keep custom settings after upgrading iRedAPD -- because iRedAPD upgrade tool will copy /opt/iredapd/settings.py to new iRedAPD release during upgrading.

Features

Sender Address Restrictions

Plugin reject_sender_login_mismatch will reject emails if:

• smtp authentication username (sasl_username) is different from sender address (From: in mail header). This is called sender login mismatch. Note: This can be performed by Postfix with restriction rule reject_sender_login_mismatch in smtpd_sender_restrictions =, but iRedAPD plugin does more work.
• sender domain is hosted on localhost, but sender doesn't perform smtp auth to send email. This is called "forged" email.

It offers some parameters to control whether or not to reject email:

• for forged sender address checking:

# Check whether sender is forged in message sent without smtp auth.
CHECK_FORGED_SENDER = True

# If you allow someone or some service providers to send email as forged
# (your local) address, you can list all allowed addresses in this parameter.
# For example, if some ISPs may send email as 'user@mydomain.com' (mydomain.com
# is hosted on your server) to you, you should add `user@mydomain.com` as one
# of forged senders.
# Sample: ALLOWED_FORGED_SENDERS = ['user@mydomain.com', 'mydomain.com']
ALLOWED_FORGED_SENDERS = []

• for sender login mismatch:

# Allow sender login mismatch for specified senders or sender domains.
#
# Sample setting: allow local user `user@local_domain_1.com` and all users
# under `local_domain_2.com` to send email as other users.
#
#   ALLOWED_LOGIN_MISMATCH_SENDERS = ['user@local_domain_1.com', 'local_domain_2.com']
ALLOWED_LOGIN_MISMATCH_SENDERS = []

# Strictly allow sender to send as one of user alias addresses. Default is True.
ALLOWED_LOGIN_MISMATCH_STRICTLY = True

# Allow member of mail lists/alias account to send email as mail list/alias
# ('From: <email_of_mail_list>' in mail header). Default is False.
ALLOWED_LOGIN_MISMATCH_LIST_MEMBER = False

White/Blacklisting

How to disable white/blacklists completely

To disable white/blacklists completely, please remove plugin name amavisd_wblist in iRedAPD config file /opt/iredapd/settings.py, parameter plugins =:

plugins = [..., 'amavisd_wblist', ...]

Restarting iRedAPD service is required.

Manage white/blacklists

• White/blacklisting is available in iRedAPD-1.4.4 and later releases.
• Script tools/wblist_admin.py is available in iRedAPD-1.7.0 and later releases.

White/blacklisting is controlled by plugin amavisd_wblist (file /opt/iredapd/plugins/amavisd_wblist.py), you can manage it with script /opt/iredapd/tools/wblist_admin.py.

Available arguments

    --outbound
        Manage white/blacklist for outbound messages.

        If no '--outbound' argument, defaults to manage inbound messages.

    --account account
        Add white/blacklists for specified (local) account. Valid formats:

            - a single user: username@domain.com
            - a single domain: @domain.com
            - entire domain and all its sub-domains: @.domain.com
            - anyone: @. (the ending dot is required)

        if no '--account' argument, defaults to '@.' (anyone).

    --add
        Add white/blacklists for specified (local) account.

    --delete
        Delete specified white/blacklists for specified (local) account.

    --delete-all
        Delete ALL white/blacklists for specified (local) account.

    --list
        Show existing white/blacklists for specified (local) account. If no
        account specified, defaults to manage server-wide white/blacklists.

    --whitelist sender1 [sender2 sender3 ...]
        Whitelist specified sender(s). Multiple senders must be separated by a space.

    --blacklist sender1 [sender2 sender3 ...]
        Blacklist specified sender(s). Multiple senders must be separated by a space.

    WARNING: Do not use --list, --add-whitelist, --add-blacklist at the same time.

Valid formats of whitelisted and blacklisted addresses

• a single user: user@domain.com
• a single domain: @domain.com, @sub.domain.com
• entire domain and all its sub-domains: @.domain.com (there's a dot after @)
• anyone: @. (the ending dot is required). it catches all addresses.
• top-level domain: @.com
• single ip address: 192.168.1.2
• CIDR network: 192.168.1.0/24

Sample usages

• Show and add server-wide whitelists or blacklists:

python3 wblist_admin.py --list --whitelist
python3 wblist_admin.py --list --blacklist

# Whitelist IP address, email address, entire domain, subdomain (including main domain)
python3 wblist_admin.py --add --whitelist 192.168.1.10 user@domain.com @iredmail.org @.example.com

# Blacklist IP address, email address, entire domain, subdomain (including main domain)
python3 wblist_admin.py --add --blacklist 202.96.134.133 bad-user@domain.com @bad-domain.com @.sub-domain.com

• For per-user or per-domain whitelists and blacklists, please use option --account. for example:

python3 wblist_admin.py --account @mydomain.com --add --whitelist 192.168.1.10 user@example.com
python3 wblist_admin.py --account user@mydomain.com --add --blacklist 172.16.1.10 baduser@example.com

python3 wblist_admin.py --account @mydomain.com --list --whitelist
python3 wblist_admin.py --account user@mydomain.com --list --blacklist

Greylisting

For technical details about greylisting, please visit http://projects.puremagic.com/greylisting/whitepaper.html.

How to disable greylisting service globally

To disable greylisting global, please run command below:

python3 /opt/iredapd/tools/greylisting_admin.py --disable --from '@.'

General settings

There're several settings for greylisting behaviour, default values are defined in /opt/iredapd/libs/default_settings.py. If you want to modify them, please add the settings with custom values in /opt/iredapd/settings.py.

• GREYLISTING_TRAINING_MODE: enable greylisting service, but don't reject any emails. This training mode is useful if this is a new mail server, it collects information of sender servers for further use.
• GREYLISTING_MESSAGE: the rejection message which will be sent to sender server. Default is Intentional policy rejection, please try again later.
• GREYLISTING_BLOCK_EXPIRE: Time (in MINUTES) to wait before client retrying, client will be rejected if retires too soon (in less than specified minutes). Defaults to 15 minutes.
• GREYLISTING_AUTH_TRIPLET_EXPIRE: Disable greylisting for how long (in DAYS) for clients which passed greylisting (retried and delivered). It's also used to clean up old greylisting tracking records. Defaults to 30 days.
• GREYLISTING_UNAUTH_TRIPLET_EXPIRE: Time (in DAYS) to keep tracking records if client didn't pass the greylisting, and no further deliver attempts. Defaults to 2 days.

Manage greylisting settings

• Script tools/greylisting_admin.py is available in iRedAPD-1.8.0 and later releases.

Greylisting is controlled by plugin greylisting (file /opt/iredapd/plugins/greylisting.py), you can manage it with script /opt/iredapd/tools/greylisting_admin.py.

Available arguments

    --list-whitelist-domains
        Show ALL whitelisted sender domain names (in `greylisting_whitelist_domains`)

    --list-whitelists
        Show ALL whitelisted sender addresses (in `greylisting_whitelists`)

    --whitelist-domain
        Whitelist the IP addresses/networks in SPF record of specified sender
        domain for greylisting service. Whitelisted domain is stored in sql
        table `greylisting_whitelist_domains`.

    --remove-whitelist-domain
        Remove whitelisted sender domain

    --list
        Show ALL existing greylisting settings.

    --from <from_address>
    --to <to_address>
        Manage greylisting setting from email which is sent from <from_address>
        to <to_address>.

        Valid formats for both <from_address> and <to_address>:

            - a single user: username@domain.com
            - a single domain: @domain.com
            - entire domain and all its sub-domains: @.domain.com
            - anyone: @. (the ending dot is required)

        if no '--from' or '--to' argument, defaults to '@.' (anyone).

    --enable
        Explicitly enable greylisting for specified account.

    --disable
        Explicitly disable greylisting for specified account.

    --delete
        Delete specified greylisting setting.

Sample usages

• List all existing greylisting settings:

python3 greylisting_admin.py --list

• List all whitelisted sender domain names (in SQL table greylisting_whitelist_domains):

python3 greylisting_admin.py --list-whitelist-domains

• List all whitelisted sender addresses (in SQL table greylisting_whitelists):

python3 greylisting_admin.py --list-whitelists

• Whitelist IP networks/addresses specified in sender domain:

python3 greylisting_admin.py --whitelist-domain --from '@example.com'

This is same as:

python3 spf_to_whitelist_domains.py --submit example.com

• Remove a whitelisted sender domain:

python3 greylisting_admin.py --remove-whitelist-domain --from '@example.com'

• Enable greylisting for emails which are sent from anyone to local mail domain example.com:

python3 greylisting_admin.py --enable --to '@example.com'

• Disable greylisting for emails which are sent from anyone to local mail user user@example.com:

python3 greylisting_admin.py --disable --to 'user@example.com'

• Disable greylisting for emails which are sent from gmail.com to local mail user user@example.com:

python3 greylisting_admin.py --disable --from '@gmail.com' --to 'user@example.com'

• Disable greylisting for sender IP:

python3 greylisting_admin.py --disable --from '45.56.127.226'

• Delete greylisting setting for emails which are sent from anyone to local domain test.com:

python3 greylisting_admin.py --delete --to '@test.com'

RECOMMENDED: Additional greylisting whitelist support

Since many companies setup their mail servers to re-deliver returned email immediately from another server, this causes trouble with greylisting.

Possible solutions:

1. Disable greylisting on your server completely.
2. [Recommended] Whitelist IP addresses/networks of their mail servers.

For solution #2, you can whitelist those mail servers with script /opt/iredapd/tools/spf_to_greylist_whitelists.py.

It queries SPF and MX records of specified mail domain names, then store all converted IP addresses/networks defined in SPF/MX records in SQL table iredapd.greylisting_whitelists.

To whitelist IP addresses/networks of some mail domain, for example, outlook.com, microsoft.com, please run command like below:

cd /opt/iredapd/tools/
python3 spf_to_greylist_whitelists.py outlook.com microsoft.com

If you want to whitelist more mail domains, just run the command with the domain names like above sample.

Since iRedAPD-1.8.0, we have SQL table iredapd.greylisting_whitelist_domains to store these mail domain names. if you run spf_to_greylist_whitelists.py without any argument, it will fetch all mail domains stored in sql table greylisting_whitelist_domains instead of fetching from command line arguments.

python3 spf_to_greylist_whitelists.py

You should setup a cron job to run this script, so that it can keep the IP addresses/networks up to date. iRedMail sets up the cron job to run every 10 or 30 minutes, like below:

*/30   *   *   *   *   /usr/bin/python3 /opt/iredapd/tools/spf_to_greylist_whitelists.py &>/dev/null