Configure postfix to relay mails using Gmail

Install postfix

Create file


Save and exit editor. Run

Edit postfix configuration file

Find and remove

At end of the file, add

Restart postfix

Now all mails will be forwarded using gmail.

Test Email Delivery

Install mailutils

To sent test email, run

Check mail log

See postfix


Zimbra Unable to validate certificate chain

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

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 witch CA Certificate files are placed. Here is zimba documentaion related to this issue

I checked with SSL provider, they initially provided a combined SSL certificate, that have 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 differnt files.


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

The provided files are

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

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

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

Edited the file

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

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

Now installed SSL with

Now rebooted the server, after reboot SSL worked.

Migrate Emails using imapcopy

To instal imapcopy on Ubuntu/Debian, run

To migrate mailbox, create a file

Create config file

In above file, replace SOURCE and DESTINATION server IP, user and passwords.

To start the email migration, run

You can test the config with command


Install Open Source Zimbra Mail Server

To install Zimbra, Download latest version form

At the time of this post, latest version is 8.8.8 GA Release.

System Requirments

Zimbra recommends 8 GB of RAM. For detailed system requirements, see Zimbra System Requirements

I have installed on servers with 4 GB RAM with out any problem. If you are installing on server with 4 GB RAM, make sure you add swap in cause you run out of RAM.

Set Hostname

Zimbra need you set set proper hostname for your server. First add an A record for your host name and point it to your server IP.

Now edit /etc/hosts and add an entry like

Where is your FQDN.

Set MX Record

During installation Zimbra check for MX record, so make sure you set MX record for your domain, point it to the server where you install Zimbra.

Install Zimbra

To install Zimbra, run

It will ask some questions. Most questions, you can just press enter as that is default option (Y).

Once install is done, you will be asked to set admin password.

After install is done, you will be able to login to Zimbra Admin area at

Web mail available at


Amazon Workmail

Amazon Workmail Review

Amazon Workmail is business email hosting like Google G Suite, Office 365, etc..

Workmail cost $4 per user, comes with 50 GB storage.

It come with all normal access modes like IMAP, POP3, etc..

Webmail is basic with contacts and Calendar.

Amazon Workmail

Since i am used to Google G Suite, it feel little hard for me to use.

One thing i noticed is when i sent email, i used to type recipient email address, press tab, enter subject, tag again, type message. This is the workflow i am used to in Google G Suite. When i try same in Amazon Workmail, it did not work because there are too many elements on the compose email screen and i have to press TAB multiple times to get into subject or body field.

Amazon Workmail Compose

All the marked elements here force you to press TAB. After enter recipient, you need to press TAB 3 times to get into subject field, again TAB 4 times before you can start wring the message.

To get to compose, you need to click “New Item” then select “New email” from drop down menu. That is lot of wasted time on a Mail application where primary purpose is to sent and receive emails. It will be better to have a “Compose” or “New email” button like most other email providers, make easy for users.

I don’t think i can compare it with Google G Suite as it come with much more features like Google Drive, Documents and many more. But for business use, many of these may not required, it depends on the business.