Difference between revisions of "King0770-Notes-Ultra-Restrictive-Sending-And-Receiving"

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<strong>The contents of this article are not yet complete and should be considered highly experimental.</strong>
 
 
Scenario: Restrict users from sending messages externally, and only receive messages from their local domain.
 
 
==Section I - Edit smtpd_sender_restrictions.cf==
 
Backup the original file
 
<code><pre>
 
cp -p /opt/zimbra/conf/zmconfigd/smtpd_sender_restrictions.cf /opt/zimbra/conf/zmconfigd/ORIG_smtpd_sender_restrictions.cf
 
</pre></code>
 
 
Edit smtpd_sender_restrictions.cf to contain only the following.
 
<code><pre>
 
check_sender_access lmdb:/opt/zimbra/conf/allowed_domains
 
reject
 
</pre></code>
 
 
Make sure to review zimbraMtaSmtpdSenderRestrictions as well.
 
<code><pre>
 
zmprov gacf | grep zimbraMtaSmtpdSenderRestrictions
 
 
**OR**
 
 
zmprov gs zimbra-mta.example.com | grep zimbraMtaSmtpdSenderRestrictions
 
</pre></code>
 
 
Should see this.
 
<code><pre>
 
zimbraMtaSmtpdSenderRestrictions: check_sender_access lmdb:/opt/zimbra/conf/allowed_domains, reject
 
</pre></code>
 
 
If needed...
 
<code><pre>
 
zmprov mcf +zimbraMtaSmtpdSenderRestrictions "check_sender_access lmdb:/opt/zimbra/conf/allowed_domains, reject"
 
</pre></code>
 
 
==Section II  - Edit allowed_domains file==
 
The /opt/zimbra/conf/allowed_domains should contain your local domains within your Zimbra setup.
 
<code><pre>
 
for dom in `zmprov gad`; do echo "$dom  OK" >> /opt/zimbra/conf/allowed_domains; done
 
</pre></code>
 
 
Should look something like this; as an example
 
<code><pre>
 
abcdcompany.com    OK
 
example.net      OK
 
</pre></code>
 
 
Don't forget to run postmap against the allowed_domains file
 
<code><pre>
 
postmap /opt/zimbra/conf/allowed_domains
 
</pre></code>
 
 
If you need to add a friendly domain that is external to your setup, you can use the editor of your choice, and add the external domain.
 
<code><pre>
 
yahoo.com  OK
 
zimbra.com  OK
 
</pre></code>
 
Any time the allowed_domains file is updated, don't forget to run postmap against the allowed_domains file.
 
<code><pre>
 
postmap /opt/zimbra/conf/allowed_domains
 
</pre></code>
 
 
==Section III - Edit smtpd_recipient_restrictions.cf==
 
Backup the original file
 
<code><pre>
 
cp -p /opt/zimbra/conf/zmconfigd/smtpd_recipient_restrictions.cf  /opt/zimbra/conf/zmconfigd/ORIG_smtpd_recipient_restrictions.cf
 
</pre></code>
 
 
Edit smtpd_recipient_restrictions.cf to contain only the following.
 
<code><pre>
 
check_recipient_access lmdb:/opt/zimbra/conf/allowed_domains
 
reject
 
</pre></code>
 
 
==Section IV - Restart MTA to pick up the changes==
 
<code><pre>
 
zmmtactl restart
 
</pre></code>
 
 
==Section V - Sample Logs==
 
Local zimbra user sending to an external address
 
<code><pre>
 
Nov 28 15:04:34 zimbra-mta postfix/smtpd[12022]: NOQUEUE: reject: RCPT from zimbra-mta.example.com[192.168.1.18]: 554 5.7.1 <smithj@gmail.com>: Recipient address rejected: Access denied; from=<rick@rick.local> to=<smithj@gmail.com> proto=ESMTP helo=<zimbra-mta.example.com>
 
Nov 28 15:04:34 zimbra-mta postfix/smtpd[12022]: disconnect from zimbra-mta.example.com[192.168.1.18] ehlo=1 mail=1 rcpt=0/1 quit=1 commands=3/4
 
</pre></code>
 
Most likely, the zimbra end user would see the error message of, <strong>Message not sent; one or more addresses were not accepted</strong>
 
 
External account sending to a zimbra address
 
<code><pre>
 
Nov 28 15:12:47 zimbra-mta postfix/smtpd[15371]: connect from mail.someexternalcompany.com[xx.xx.xx.xx]
 
Nov 28 15:12:47 zimbra-mta postfix/smtpd[15371]: Anonymous TLS connection established from mail.someexternalcompany.com[xx.xx.xx.xx]: TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)
 
Nov 28 15:12:47 zimbra-mta postfix/smtpd[15371]: NOQUEUE: reject: RCPT from mail.someexternalcompany.com[xx.xx.xx.xx]: 554 5.7.1 <rick@someexternalcompany.com>: Sender address rejected: Access denied; from=<rick@someexternalcompany.com> to=<rick@rick.local> proto=ESMTP helo=<mail.someexternalcompany.com>
 
Nov 28 15:12:47 zimbra-mta postfix/smtpd[15371]: disconnect from mail.someexternalcompany.com[xx.xx.xx.xx] ehlo=2 starttls=1 mail=1 rcpt=0/1 data=0/1 rset=1 quit=1 commands=6/8
 
</pre></code>
 
Most likely the external account will get a bounce message, <strong>Sender address rejected: Access denied</strong>
 
 
==Section VI - FAQ==
 
<strong>Will I need to be root to make these changes?</strong><br>
 
No, just use the zimbra account
 
 
<strong>Will these changes survive upgrades?</strong><br>
 
No
 
 
<strong>I have a domain that I need to blacklist, should I add it to the allowed_domains file? i.e.  freeipad.com    REJECT</strong><br>
 
There's no need. Domains that are <strong>NOT</strong> in the allowed_domains file will be rejected.
 
 
<strong>If I decide to implement these changes, will Zimbra Support help me if I need assistance?</strong><br>
 
This is a customization, and as such, Zimbra will <strong>not</strong> Support any custom changes. If you need to revert your changes, Zimbra Support can help.
 
 
<strong>I want my users to be able to receive messages from external domains, but still restrict what domains my users can send to, can I just edit the smtpd_recipient_restrictions.cf file, and leave the smtpd_sender_restrictions.cf file untouched?</strong><br>
 
Correct.<br>
 
 
==Section VII - Notable RFE's==
 
https://bugzilla.zimbra.com/show_bug.cgi?id=70599<br>
 
https://bugzilla.zimbra.com/show_bug.cgi?id=5595<br>
 
 
==Section VIII - Advanced Configuration==
 
<strong>NOT COMPLETE!!!</strong><br>
 
If you wanted to use a different method, you can use the smtpd_restriction_classes setting.<br>
 
For example, if you have just one domain in your zimbra setup, and you want all your internal users to be able to send messages to; however, there is <strong>one</strong> account that needs to be able to an external domain, say for example yahoo.com, here's what you can do.
 
 
a) Edit /opt/zimbra/conf/zmconfigd.cf with the following
 
<code><pre>
 
POSTCONF smtpd_restriction_classes  internal_only, yahoo_only
 
POSTCONF internal_only  check_sender_access lmdb:/opt/zimbra/conf/internal_only, reject
 
POSTCONF yahoo_only    check_sender_access lmdb:/opt/zimbra/conf/yahoo_only, reject
 
</pre></code>
 
 
Place the lines just above the <strong>RESTART mta</strong>
 
 
b) Create the /opt/zimbra/conf/internal_only with your local zimbra domains
 
<code><pre>
 
abcdcompany.com    OK
 
</pre></code>
 
 
And run postmap against the file
 
<code><pre>
 
postmap /opt/zimbra/conf/internal_only
 
</pre></code>
 
 
c) Create the /opt/zimbra/conf/yahoo_only file with the following
 
<code><pre>
 
yahoo.com    OK
 
</pre></code>
 
 
d) Create the /opt/zimbra/conf/internal_permitted file with the following
 
<code><pre>
 
abcdcompany.com internal_only
 
</pre></code>
 
 
e) Create the /opt/zimbra/conf/yahoo_permitted file with the following
 
<code><pre>
 
boss@abcdcompany.com yahoo_only
 
</pre></code>
 
 
f) Run postmap against the files
 
<code><pre>
 
postmap  /opt/zimbra/conf/internal_permitted
 
postmap /opt/zimbra/conf/yahoo_permitted
 
</pre></code>
 
 
g) Edit the /opt/zimbra/conf/zmconfigd/smtpd_sender_restrictions.cf with the following
 
<code><pre>
 
check_sender_access lmdb:/opt/zimbra/conf/internal_permitted
 
check_sender_access lmdb:/opt/zimbra/conf/yahoo_permitted, reject
 
</pre></code>
 
 
h) Edit the /opt/zimbra/conf/zmconfigd/smtpd_recipient_restrictions.cf with the following
 
<code><pre>
 
check_recipient_access lmdb:/opt/zimbra/conf/internal_permitted
 
check_recipient_access lmdb:/opt/zimbra/conf/yahoo_permitted, reject
 
</pre></code>
 
 
i) Restart MTA
 
<code><pre>
 
zmmtactl restart
 
</pre></code>
 
 
j) Should have the following
 
<code><pre>
 
postconf smtpd_restriction_classes smtpd_sender_restrictions smtpd_recipient_restrictions
 
 
smtpd_restriction_classes = internal_only, yahoo_only
 
smtpd_sender_restrictions = check_sender_access lmdb:/opt/zimbra/conf/internal_permitted, check_sender_access lmdb:/opt/zimbra/conf/yahoo_permitted, reject
 
smtpd_recipient_restrictions = check_recipient_access lmdb:/opt/zimbra/conf/internal_permitted, check_recipient_access lmdb:/opt/zimbra/conf/yahoo_permitted, reject
 
</pre></code>
 

Revision as of 20:09, 2 February 2018

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