This option works only if you have rebuilt the mail server in cwp.admin with antispam.
You can blacklist or whitelist incoming emails in the following files:

/etc/postfix/sender_blacklist
/etc/postfix/sender_whitelist

After making changes you need to run the following command for the files you edited

postmap /etc/postfix/sender_blacklist
postmap /etc/postfix/sender_whitelist

Options:
# Example for blacklisting domains/IP's or emails, one per line:

1.2.3.4 REJECT
1.2.3.5 REJECT
mail.freemailer.tld REJECT We don't allow emails from mail.freemailer.tld
test@test.test REJECT

After REJECT you can add the message which will be returned to the sender.
The whitelist is the same only difference is that instead of REJECT you use OK.

Example for whitelisting domains/IP's, one per line:

1.2.3.4 OK
1.2.3.5 OK
mail.freemailer.tld OK
test@test.test OK

In the user panel, you can do that by using DNS Zone Editor.
Add New TXT Record and make sure you split 2048 bit long key in half and wrap in quotes.

Example of the full key:

v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAlTtO1qRFaK955gz16Y8c1EMCqtaT4exCrwfor2yT438ZVjrUcqo2tPUNR4eqkD+xcKRQnWSw931uVUY6YJWtOrgrXTIrHnTkf5Xtg+jaXr0OhjdeVDIG/Le7oOVWncMf+9J4ZSRybOpb+XZPp/JLjis6pmCLrt5j82yBC9DCbsEPSOVVOC1mr5lq8irQs+qAv6M/DnjNcUrdiRBJyNrs2lfuvfs8BFceZAk1AwcVBcYCmZl5OkxZBn8liTC34FPJLLHm6jMp9+c0OaEtxo8zr3QX0ZYEWC3XqZ/p9fo4Pcg+fpyjee79wBVqUzhVAWdzE5+qAIn4e1Dmslyb6IX4mwIDAQAB

Example of key split, first half:

v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAlTtO1qRFaK955gz16Y8c1EMCqtaT4exCrwfor2yT438ZVjrUcqo2tPUNR4eqkD+xcKRQnWSw931uVUY6YJWtOrgrXTIrHnTkf5Xtg+jaXr0OhjdeVDIG/Le7oOVWncMf+9J4ZSRybOpb+XZPp/JLjis6pmC

second half:

Lrt5j82yBC9DCbsEPSOVVOC1mr5lq8irQs+qAv6M/DnjNcUrdiRBJyNrs2lfuvfs8BFceZAk1AwcVBcYCmZl5OkxZBn8liTC34FPJLLHm6jMp9+c0OaEtxo8zr3QX0ZYEWC3XqZ/p9fo4Pcg+fpyjee79wBVqUzhVAWdzE5+qAIn4e1Dmslyb6IX4mwIDAQAB

And now you can add it like this, both parts wrapped in the quotes:

"v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAlTtO1qRFaK955gz16Y8c1EMCqtaT4exCrwfor2yT438ZVjrUcqo2tPUNR4eqkD+xcKRQnWSw931uVUY6YJWtOrgrXTIrHnTkf5Xtg+jaXr0OhjdeVDIG/Le7oOVWncMf+9J4ZSRybOpb+XZPp/JLjis6pmC" "Lrt5j82yBC9DCbsEPSOVVOC1mr5lq8irQs+qAv6M/DnjNcUrdiRBJyNrs2lfuvfs8BFceZAk1AwcVBcYCmZl5OkxZBn8liTC34FPJLLHm6jMp9+c0OaEtxo8zr3QX0ZYEWC3XqZ/p9fo4Pcg+fpyjee79wBVqUzhVAWdzE5+qAIn4e1Dmslyb6IX4mwIDAQAB"

* Wrap in quotes both parts and split it by space in the same line.

Manual Instructions:

As an admin, you can also add it manually by editing the DNS zone file in /var/named/DOMAIN.COM.db ,example:

default._domainkey 14400 IN TXT "v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAlTtO1qRFaK955gz16Y8c1EMCqtaT4exCrwfor2yT438ZVjrUcqo2tPUNR4eqkD+xcKRQnWSw931uVUY6YJWtOrgrXTIrHnTkf5Xtg+jaXr0OhjdeVDIG/Le7oOVWncMf+9J4ZSRybOpb+XZPp/JLjis6pmC" "Lrt5j82yBC9DCbsEPSOVVOC1mr5lq8irQs+qAv6M/DnjNcUrdiRBJyNrs2lfuvfs8BFceZAk1AwcVBcYCmZl5OkxZBn8liTC34FPJLLHm6jMp9+c0OaEtxo8zr3QX0ZYEWC3XqZ/p9fo4Pcg+fpyjee79wBVqUzhVAWdzE5+qAIn4e1Dmslyb6IX4mwIDAQAB"

Then reload named/bind

service named reload

TESTING

The output should show the full dkim line

dig TXT default._domainkey.DOMAIN.COM @10.10.10.10

* replace DOMAIN.COM and IP 10.10.10.10 with CWP IP

sa-learn -p /home/USER/.spamassassin/user_prefs --spam /var/vmail/DOMAIN.TLD/ACCOUNT/.Junk/{cur,new}

By default, SpamAssassins will deny messages or save them in the folder /var/vmail/DOMAIN.TLD/ACCOUNT/.Spam/

Learn SpamAssassins about NOT spam messages
Before starting, by using your mail client move all valid messages to a custom folder named Seen and then scan it with --ham, example:

sa-learn -p /home/USER/.spamassassin/user_prefs --ham /var/vmail/DOMAIN.TLD/ACCOUNT/.Seen/{cur,new}

Don't forget to replace USER, DOMAIN.TLD, and ACCOUNT
Example for mailbox john@testaccount.com owned by system user testacc:

sa-learn -p /home/testacc/.spamassassin/user_prefs --spam /var/vmail/testaccount.com/john/.Junk/{cur,new}

More info about SpamAssassins
https://spamassassin.apache.org/full/3.1.x/doc/sa-learn.html

Test ClamAV

Send an email with content

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

If ClamAV works you will see the following in the log: /var/log/maillog

Dec 27 07:22:42 cwp1 clamd[17958]: /var/spool/amavisd/tmp/amavis-20211227T071305-18132-Ocyoo8yY/parts/p001: {HEX}EICAR.TEST.3.UNOFFICIAL FOUND

Dec 27 07:22:42 cwp1 amavis[18132]: (18132-02) Blocked INFECTED ({HEX}EICAR.TEST.3.UNOFFICIAL) {DiscardedOpenRelay,Quarantined}, [209.85.216.47]:46925 [209.85.216.47]  -> , Queue-ID: 9762E703FD2, Message-ID: , mail_id: TKHZnGx2Bs7T, Hits: -, size: 3868, dkim_sd=20210112:gmail.com, 111 ms

Dec 27 07:22:42 cwp1 postfix/smtp[12663]: 9762E703FD2: to=, relay=127.0.0.1[127.0.0.1]:10024, delay=0.34, delays=0.21/0.02/0/0.11, dsn=2.7.0, status=sent (250 2.7.0 Ok, discarded, id=18132-02 - INFECTED: {HEX}EICAR.TEST.3.UNOFFICIAL)

Test SpamAssassin

Send an email with content:

XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X

If SpamAssassin works you will see the following in the log: /var/log/maillog

Dec 27 07:25:37 cwp1 amavis[18133]: (18133-02) Blocked SPAM {DiscardedOpenRelay,Quarantined}, [209.85.215.174]:37637 [209.85.215.174]  -> , Queue-ID: 59C16703FD2, Message-ID: , mail_id: vES-jRB7LKPt, Hits: 999.904, size: 3903, dkim_sd=20210112:gmail.com, 579 ms

First run the CWP Update script that will ensure you've latest version of CWP :

sh /scripts/update_cwp

Second run the CWP roundcube update script :

sh /scripts/mail_roundcube_update

This will install supported version of Roundcube and error will be fixed, if you're still getting internal error then you need run this script to fix the mail permissions :

/scripts/cwp_api account mail_fix_permissions

* pleas note that on servers with big /var/vmail folder this can take some time

Make sure you also check the logs
/usr/local/cwpsrv/var/services/roundcube/logs/errors.log
/var/log/dovecot.log

Permissions for /var/vmail

chown vmail.mail /var/vmail
chmod 770 /var/vmail

File: /etc/postfix/master.cf

smtp	  inet  n	-	n	-	-	smtpd
  -o content_filter=smtp-amavis:127.0.0.1:10024
  -o receive_override_options=no_address_mappings

After no_address_mappings add no_milters , example:

smtp	  inet  n	-	n	-	-	smtpd
  -o content_filter=smtp-amavis:127.0.0.1:10024
  -o receive_override_options=no_address_mappings,no_milters

After changes restart postfix:

service postfix restart

If you see in your postfix log file /var/log/maillog messages like:

Mar 29 08:13:02 cwp-mailserver postfix/smtp[12934]: A35C2137013: to=, relay=gmail-smtp-in.l.google.com[173.194.69.26]:25, delay=1.1, delays=0.1/0.02/0.61/0.34, dsn=5.7.1, status=bounced (host gmail-smtp-in.l.google.com[173.194.69.26] said: 550-5.7.1 [85.111.34.35      12] Our system has detected that this message is 550-5.7.1 likely unsolicited mail. To reduce the amount of spam sent to Gmail, 550-5.7.1 this message has been blocked. Please visit 550-5.7.1  https://support.google.com/mail/?p=UnsolicitedMessageError 550 5.7.1  for more information. hc31si12141407ejc.524 - gsmtp (in reply to end of DATA command))

This can mean in some cases that gmail blocked your domain and/or IP address.
In a case of the blocked domain when you resolve the issue with spam they could continue to block all the emails for the next 30 days.

/@customer1-dom\.tld$/		customer1:
/@customer2-dom\.tld$/		customer2:
/@customer3-dom\.tld$/		customer3:
..... next .....

In master.cf create special transport called customer1, customer2, customer3….and so on

customer1  unix -       -       n       -       -       smtp
   -o smtp_bind_address=1.1.1.1
   -o smtp_helo_name=customer1-dom.tld
   -o syslog_name=postfix-customer1

customer2  unix -       -       n       -       -       smtp
   -o smtp_bind_address=1.1.1.2
   -o smtp_helo_name=customer2-dom.tld
   -o syslog_name=postfix-customer2

customer3  unix -       -       n       -       -       smtp
   -o smtp_bind_address=1.1.1.3
   -o smtp_helo_name=customer3-dom.tld
   -o syslog_name=postfix-customer3

..... next .....

In main.cf add sender_dependent_default_transport_maps line:

sender_dependent_default_transport_maps = regexp:/etc/postfix/sdd_transport_maps.regexp

Don’t forget to create ip aliasing for each ip address in smtp_bind_address

reload/ restart postfix

# service postfix restart

to set for server-wide for all clients
You want smtp_bind_address=66.66.66.67 and inet_interfaces=all
or inet_interfaces=eth(whatever) that 66.66.66.67 is on.
and RESTART postfix

sh /scripts/mail_roundcube_update

The latest version will also bring you the new RoundCube skin elastic.

If you skin is not set to elastic you can do it by yourself
- check that you have this folder: /usr/local/cwpsrv/var/services/roundcube/skins/elastic
- then run the command to set the elastic skin as default

sed -i "s/larry/elastic/g" /usr/local/cwpsrv/var/services/roundcube/config/config.inc.php

In the "Redirects to:" option, you can enter any email address and all email coming for *@domain1.com will be forwarded to "Redirects to:" email address which can be for example catchall@domain2.com