Category: Mail

iredmail increase mail attachment size
Default mail attachment size in iredmail is 10 MB. To increase mail attachment size, login to server as user root, run following commands
```
postconf -e message_size_limit=104857600
postconf -e mailbox_size_limit=104857600
systemctl restart postfix
```
Here 104857600 is 100 MB in bytes (100 * 1024 * 1024). Change this as required. Sending very large file using mail attachment is not recommended, it is better use file sharing services like Google Drive, Dropbox, Microsoft OneDrive or another file hosting service for sharing large files.

Now edit php.ini file
```
vi /etc/php/7.2/fpm/php.ini
```
Change value for 3 of the following settings. It can be anything above 100 MB or whatever attachment size you want to use.
```
memory_limit = 256M;
upload_max_filesize = 100M;
post_max_size = 120M;
```
Restart php-fpm
```
systemctl restart php7.2-fpm
```
Edit roundcube configuration file
```
vi /opt/www/roundcubemail/config/config.inc.php
```
Set value for
```
$config['max_message_size'] = '100M';
```
Edit Nginx config file
```
vi /etc/nginx/conf-available/client_max_body_size.conf
```
Set value for
```
client_max_body_size 100m;
```
restart nginx
```
systemctl restart nginx
```
January 29, 2020

Zimbra webmail not working on port 80/443

On Zimbra mail server, webmail stopped working on Port 80/443. Admin interface worked properly on url https://hostname:7071/. There is no errors displayed under monitor tab of Zimbra Admin.

To fix, run

su - zimbra
zmprov ms `zmhostname` zimbraReverseProxySSLToUpstreamEnabled FALSE
zmprov ms `zmhostname` zimbraMailMode both
zmprov ms `zmhostname` zimbraReverseProxyMailMode both
./libexec/zmproxyconfig -e -w -o -a 8080:80:8443:443 -x both -H `zmhostname`
zmcontrol restart

After running this, netstat -lntp start showing nginx running on port 80 and 443

root@zim:~# netstat -lntp | egrep "80|443"
tcp        0      0 127.0.0.1:10663         0.0.0.0:*               LISTEN      10980/zmlogger: zmr
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      11354/nginx.conf
tcp        0      0 127.0.0.1:8080          0.0.0.0:*               LISTEN      11098/java      
tcp        0      0 116.203.102.86:8080     0.0.0.0:*               LISTEN      11098/java      
tcp        0      0 0.0.0.0:443             0.0.0.0:*               LISTEN      11354/nginx.conf
tcp6       0      0 :::7780                 :::*                    LISTEN      11707/httpd     
root@zim:~#

September 6, 2019

Zimbra Mail Server CentOS firewall settings

On CentOS 7 server with firewalld running, used following command to open ports used by Zimbra Mail Server.

firewall-cmd --zone=public --permanent --add-service=http
firewall-cmd --zone=public --permanent --add-service=https
firewall-cmd --zone=public --permanent --add-service=ssh
firewall-cmd --zone=public --permanent --add-port=110/tcp
firewall-cmd --zone=public --permanent --add-port=11211/tcp
firewall-cmd --zone=public --permanent --add-port=143/tcp
firewall-cmd --zone=public --permanent --add-port=25/tcp
firewall-cmd --zone=public --permanent --add-port=443/tcp
firewall-cmd --zone=public --permanent --add-port=465/tcp
firewall-cmd --zone=public --permanent --add-port=5222/tcp
firewall-cmd --zone=public --permanent --add-port=5269/tcp
firewall-cmd --zone=public --permanent --add-port=587/tcp
firewall-cmd --zone=public --permanent --add-port=7025/tcp
firewall-cmd --zone=public --permanent --add-port=7071/tcp
firewall-cmd --zone=public --permanent --add-port=7072/tcp
firewall-cmd --zone=public --permanent --add-port=7073/tcp
firewall-cmd --zone=public --permanent --add-port=7110/tcp
firewall-cmd --zone=public --permanent --add-port=7143/tcp
firewall-cmd --zone=public --permanent --add-port=7993/tcp
firewall-cmd --zone=public --permanent --add-port=7995/tcp
firewall-cmd --zone=public --permanent --add-port=8443/tcp
firewall-cmd --zone=public --permanent --add-port=993/tcp
firewall-cmd --zone=public --permanent --add-port=995/tcp
firewall-cmd --reload

See Zimbra, firewall-cmd

August 9, 2019

Zimbra redirect webmail http to https

After Zimbra mail server installed, webmail work on url

https://SERVER-HOSTNAME-HERE/

If you access webmail with out HTTPS, it won’t work.

To set HTTP to redirect to HTTPS, login to server as root, switch to user zimbra

su - zimbra

Run

zmprov ms SERVER_HOSTNAME_HERE zimbraReverseProxyMailMode redirect

Wait few minutes, HTTP link will redirect to HTTPS.

[root@correo ~]# netstat -lntp | grep 80                                                                                                                                                                    
tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      22891/java                                                                                                                  
tcp6       0      0 :::7780                 :::*                    LISTEN      24005/httpd                                                                                                                 
[root@correo ~]# su - zimbra                                                                                                                                                                                
Last login: Thu Aug  8 21:33:52 CST 2019 on pts/0                                                                                                                                                           
[zimbra@correo ~]$ zmprov ms correo.net.gt zimbraReverseProxyMailMode redirect                                                                                                                              
[zimbra@correo ~]$

You need to wait few minutes before it can start working on HTTPS port, no restart required.

Now netstat shows nginx runs on port 80

[root@correo ~]# netstat -lntp| grep 80
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      90391/nginx: master 
tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      22891/java          
tcp6       0      0 :::7780                 :::*                    LISTEN      24005/httpd         
[root@correo ~]#

See Zimbra

August 9, 2019

Install SSL Certificate on Zimbra mail server

To install SSL certificate for Zimbra Mail Server, login to server, switch to user zimbra

su - zimbra

Now create file commercial.key, paste your Private key.

vi /opt/zimbra/ssl/zimbra/commercial/commercial.key

In commercial.crt, paste your SSL certificate.

vi /opt/zimbra/ssl/zimbra/commercial/commercial.crt

Create commercial_ca.crt with content of your ca-bundle file.

vi /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt

Verify SSL cerificate

/opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key  /opt/zimbra/ssl/zimbra/commercial/commercial.crt

If SSL verified sucessfully, you can install it with command

/opt/zimbra/bin/zmcertmgr deploycrt comm  /opt/zimbra/ssl/zimbra/commercial/commercial.crt /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt

To make SSL active, you need to restart Zimbra mail server with command

zmcontrol restart

August 9, 2019

Email Marketing

https://sendpulse.com – Free upto 500 subscribers.
https://convertkit.com – Free upto 1000 subscribers.
https://mailchimp.com – Free upto 2000 subscribers.
https://www.gmass.co – Allow you to send mass email using Gmail and G Suite.
OpenEMM – Install instructions.
https://yamm.com
https://www.klaviyo.com – email marketing
https://github.com/AfterShip/email-verifier – email verifier
https://www.lemlist.com/cold-email-templates – Cold Email Templates.

Find Email

https://anymailfinder.com – find email address of business owner.
https://www.apollo.io/ – Apollo is too for cold-outbound email. They have access to everyone’s email with 99% accuracy and a super simple drip sequence.

Marketing Ideas

https://marketingexamples.com
https://www.facebook.com/ads/library/ – see all currently running facebook ads.
https://reallygoodemails.com – email templates.

Other Useful

https://www.hotjar.com – see what visitors doing on your website.
https://www.similarweb.com – See what your competition doing.

July 21, 2019
DMARC
DMARC is used to protect your email from email spoofing. DMARC use SPF and DKIM record to validate your email.

DMARC is a TXT record added in your domain DNS.

DMARC record look like
```
v=DMARC1;p=POLICY_HERE;pct=100;rua=mailto:[email protected];ruf=mailto:[email protected];rf=afrf
```
p=POLICY_HERE

This specifies what to do with incoming email that fails DMARC.

Valid options are none, quarantine and reject.

p=none – used for monitoring. If DMARC fails, the remote mail server will send a mail to “rua” or “ruf” tags specified in the DMARC record.

p=quarantine – tell the recipient mail server to put the message in the SPAM folder if DMARC fails.

p=reject – reject mail if DMARC fails.

rf=afrf – Specify the type of report you will get.

Reject Emails that fail DKIM/SPF check
```
v=DMARC1; p=reject; rua=mailto:[email protected]
```
Filter and Reject Only 95% mails
```
v=DMARC1; p=reject; pct=95; rua=mailto:[email protected]
```
Quarantine Emails that fail DKIM/SPF check
```
v=DMARC1; p=quarantine; rua=mailto:[email protected]
```
Back to Mail
July 11, 2019

Postfix disable IPv6

To disable IPv6 on the postfix mail server, edit

vi /etc/postfix/main.cf

Find

inet_protocols = all

Replace with

inet_protocols = ipv4

Restart postfix

systemctl restart postfix

Method 2

postconf -e inet_protocols=ipv4
systemctl restart postfix

To see the current configuration, run

[root@server ~]# postconf inet_protocols
inet_protocols = ipv4
[root@server ~]#

June 17, 2019

Configure postfix to relay mails using Gmail

Install postfix

apt update
apt install postfix libsasl2-modules

Create file

touch /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd
vi /etc/postfix/sasl_passwd

Add

[smtp.gmail.com]:587    [email protected]:password

Save and exit editor. Run

postmap /etc/postfix/sasl_passwd

Edit postfix configuration file

vi /etc/postfix/main.cf

Find and remove

relayhost =

At end of the file, add

relayhost = [smtp.gmail.com]:587
smtp_use_tls = yes
smtp_sasl_auth_enable = yes
smtp_sasl_security_options =
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

Restart postfix

systemctl restart postfix

Now all mails will be forwarded using gmail.

Test Email Delivery

Install mailutils

apt install mailutils

On CentOS

yum install mailx

To sent test email, run

echo "test" | mail -s "Testing gmail" [email protected]

Check mail log

tail -f /var/log/mail.log

See postfix

May 31, 2019

Zimbra Unable to validate certificate chain

On installing SSL on the Zimbra mail server, i get the following error

zimbra@zim:~/boby$ /opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key  /opt/zimbra/boby/zim_simplecloud_co_za.crt
** Verifying '/opt/zimbra/boby/zim_simplecloud_co_za.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/opt/zimbra/boby/zim_simplecloud_co_za.crt' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/opt/zimbra/boby/zim_simplecloud_co_za.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
ERROR: Unable to validate certificate chain: /opt/zimbra/boby/zim_simplecloud_co_za.crt: C = US, ST = New Jersey, L = Jersey City, O = The USERTRUST Network, CN = USERTrust RSA Certification Authority
error 2 at 2 depth lookup:unable to get issuer certificate
zimbra@zim:~/boby$

This was due to SSL cert chain. The ca-bundle file they provided did not work with Zimbra. This is due to some issue with the order in which CA Certificate files are placed. Here is Zimba documentation related to this issue

https://wiki.zimbra.com/wiki/Fix_depth_lookup:unable_to_get_issuer_certificate

I checked with SSL provider, and they initially provided a combined SSL certificate, that has cert file + ca certificate. I tried to install it, but it did not work.

After showing SSL support the screenshot of the SSL install page, they provided me with 3 different files.

In the zimbra SSL install, you have option to add more intermediate CA by clicking “Add Intermediate CA” link.

The provided files are

root.ca
intermediate1.ca-bundle
intermediate2.ca-bundle

I tried to install it using UI, but it failed with some errors related to RemoteManager and port 22.

To install on Command line, first you need to login as user zimbra

su - zimbra

I copied all files provided by SSL provider to the server. Change to SSL folder

cd /opt/zimbra/ssl/zimbra/commercial/

Edited the file

vi commercial.crt

Pasted the SSL certificate content to this file. commercial.key file have the private key, this get auto generated during the CSR generation process.

Now i tried mixing those 3 files (CA certs) to create commerical_ca.crt, but it failed to work

zimbra@zim:~/ssl/zimbra/commercial$ cat  ~/boby/root.crt ~/boby/intermediate1.ca-bundle > /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt
zimbra@zim:~/ssl/zimbra/commercial$ /opt/zimbra/bin/zmcertmgr verifycrt comm commercial.key commercial.crt
** Verifying 'commercial.crt' against 'commercial.key'
Certificate 'commercial.crt' and private key 'commercial.key' match.
** Verifying 'commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
ERROR: Unable to validate certificate chain: Error loading file /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt
140015104063128:error:0906D066:PEM routines:PEM_read_bio:bad end line:pem_lib.c:815:
140015104063128:error:0B084009:x509 certificate routines:X509_load_cert_crl_file:PEM lib:by_file.c:259:
zimbra@zim:~/ssl/zimbra/commercial$

After few try, mixing ca certificate in the following order got it work.

zimbra@zim:~/ssl/zimbra/commercial$ cat   ~/boby/intermediate1.ca-bundle  ~/boby/intermediate2.ca-bundle ~/boby/root.crt > /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt
zimbra@zim:~/ssl/zimbra/commercial$ /opt/zimbra/bin/zmcertmgr verifycrt comm commercial.key commercial.crt
** Verifying 'commercial.crt' against 'commercial.key'
Certificate 'commercial.crt' and private key 'commercial.key' match.
** Verifying 'commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
Valid certificate chain: commercial.crt: OK
zimbra@zim:~/ssl/zimbra/commercial$

Now installed SSL with

zimbra@zim:~/ssl/zimbra/commercial$ /opt/zimbra/bin/zmcertmgr deploycrt comm commercial.crt commercial_ca.crt
** Fixing newlines in 'commercial_ca.crt'
** Verifying 'commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate 'commercial.crt' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying 'commercial.crt' against 'commercial_ca.crt'
Valid certificate chain: commercial.crt: OK
** Copying 'commercial.crt' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
'commercial.crt' and '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' are identical (not copied) at /opt/zimbra/bin/zmcertmgr line 1278.
** Copying 'commercial_ca.crt' to '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
'commercial_ca.crt' and '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt' are identical (not copied) at /opt/zimbra/bin/zmcertmgr line 1278.
** Appending ca chain 'commercial_ca.crt' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
** Importing cert '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt' as 'zcs-user-commercial_ca' into cacerts '/opt/zimbra/common/lib/jvm/java/jre/lib/security/cacerts'
** NOTE: restart mailboxd to use the imported certificate.
** Saving config key 'zimbraSSLCertificate' via zmprov modifyServer zim.simplecloud.co.za...ok
** Saving config key 'zimbraSSLPrivateKey' via zmprov modifyServer zim.simplecloud.co.za...ok
** Installing imapd certificate '/opt/zimbra/conf/imapd.crt' and key '/opt/zimbra/conf/imapd.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/imapd.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/imapd.key'
** Creating file '/opt/zimbra/ssl/zimbra/jetty.pkcs12'
** Creating keystore '/opt/zimbra/conf/imapd.keystore'
** Installing ldap certificate '/opt/zimbra/conf/slapd.crt' and key '/opt/zimbra/conf/slapd.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/slapd.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/slapd.key'
** Creating file '/opt/zimbra/ssl/zimbra/jetty.pkcs12'
** Creating keystore '/opt/zimbra/mailboxd/etc/keystore'
** Installing mta certificate '/opt/zimbra/conf/smtpd.crt' and key '/opt/zimbra/conf/smtpd.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/smtpd.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/smtpd.key'
** Installing proxy certificate '/opt/zimbra/conf/nginx.crt' and key '/opt/zimbra/conf/nginx.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/nginx.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/nginx.key'
** NOTE: restart services to use the new certificates.
** Cleaning up 3 files from '/opt/zimbra/conf/ca'
** Removing /opt/zimbra/conf/ca/ca.key
** Removing /opt/zimbra/conf/ca/ca.pem
** Removing /opt/zimbra/conf/ca/44fca4b1.0
** Copying CA to /opt/zimbra/conf/ca
** Copying '/opt/zimbra/ssl/zimbra/ca/ca.key' to '/opt/zimbra/conf/ca/ca.key'
** Copying '/opt/zimbra/ssl/zimbra/ca/ca.pem' to '/opt/zimbra/conf/ca/ca.pem'
** Creating CA hash symlink '44fca4b1.0' -> 'ca.pem'
** Creating /opt/zimbra/conf/ca/commercial_ca_1.crt
** Creating CA hash symlink '65ff7287.0' -> 'commercial_ca_1.crt'
** Creating /opt/zimbra/conf/ca/commercial_ca_2.crt
** Creating CA hash symlink 'fc5a8f99.0' -> 'commercial_ca_2.crt'
** Creating /opt/zimbra/conf/ca/commercial_ca_3.crt
** Creating CA hash symlink '157753a5.0' -> 'commercial_ca_3.crt'
zimbra@zim:~/ssl/zimbra/commercial$

Now rebooted the server, and after reboot SSL worked.

March 19, 2019

Postfix Delete Mails from a user
To delete emails from a particular user from postfix mail queue, run
```
postqueue -p | grep USER_HERE | cut -d' '  -f1 | postsuper -d -  
```
See postfix
February 16, 2019
imap
February 9, 2019

Category: Mail

Find Email

Marketing Ideas

Other Useful

Reject Emails that fail DKIM/SPF check

Quarantine Emails that fail DKIM/SPF check

Test Email Delivery