Setting up Email forwarding System for GIT

The post is a derivative of the omapzoom wiki page. Disclaimer: my mastery of the wiki tags are dismal.. apologies... some day i hope to have time to post it here

Many new developers have been stumped when they need to use git-send-email in corporate environment – usually, if not as a norm, ms exchange servers form the backbone of such an email server system. This page was written based on one of such requirements.

To get started, we shall consider common scenarios:
a) Setting up a mail forwarding system with postfix on ubuntu
b) Setting up a mail forwarding system on a fedora machine
c) Using msmtp for using gmail
a. to send a patch using a gmail ID
b. to send a patch using your corporate ID but through gmail

Postfix on Ubuntu – mail forwarding
For setting up postfix, you need:
a) A mail relay server which will allow your machine to talk to it -> speak to your IT representatives/ other developers sitting next to you
b) Super user privileges on the machine you are working on.

Step 1: Check if the required packages are present

$ dpkg --get-selections grep postfix
postfix install

Step2: If postfix is already installed and not properly configured, uninstall the same:

$ sudo apt-get purge postfix

Do you want to continue Y/n?? y
(Reading database ... 260051 files and directories currently installed.)
Removing mailutils ...
Purging configuration files for mailutils ...
Removing postfix ...
* Stopping Postfix Mail Transport Agent postfix OK?
Purging configuration files for postfix ...
Processing triggers for libc6 ...
ldconfig deferred processing now taking place

Step3: Reinstall postfix:

$ sudo apt-get install postfix

When you install postfix, we go through a few screens as follows:

a) postfix gives a bit of help information -> read through it -> esp the idea of a “Satellite System” – this is what we will be using here.



b) postfix now asks you about what type of mail server do you wish to setup here -> say you want a “Satellite system”
c) now postfix will ask you for your machine’s domain name -> give the name of the machine you are using -> note, this is not the same as the relay server we will be using.
d) Post fix now asks for your email relay server information -> provide the complete machine information here

Postfix on Fedora – mail forwarding
Please refer 'Postfix Pre-Installation Steps', 'Installing Postfix on Fedora Linux' and 'Starting Postfix on Fedora Linux' sections of this link

Note: Before moving on to the 'Starting Postfix on Fedora Linux' section of the link, open /etc/postfix/main.cf file and edit the following parameters only

myhostname = (Enter your hostname here)
relayhost = (Put the appropriate server here for your location)

Using msmtp as the email forwarding system for gmail

Note: If you successfully configured postfix you dont need to configure msmtp.
Step 1: You now need to make a choice -> if you would like to configure your gmail account to send emails on behalf of your corporate mail ID, you need to configure gmail for the same - else skip this step ;)
a) go to gmail.com and log in with your user id and password
b) click on settings:
c) Select accounts

d) Click on “Add another email address you own”
e) A pop up appears: Fill up the required information and click on Send verification

f) Look in your mail account you added for the confirmation number:
g) Provide this to the pop up window
h) Set up gmail settings to always reply to the same email id which send the email as follows:
That is it. You can now send email from your gmail account as if it were send by your corporate account.

Step 2: Installing msmtp is as simple as “sudo apt-get install msmtp” or “sudo yum install msmtp” as required for your distro.. worst case you can build and install it yourself from http://msmtp.sourceforge.net/

Step 3: You now need to configure msmtp -> create a ~/.msmtprc file with permissions for 400 (user readonly).. as follows:

# Example for a user configuration file
# Set default values for all
following accounts.
defaults
tls on
# The ca-bundle.crt is the file
with CA certificates for Fedora Core 6.
# for other distros you might have
to dig it up from somewhere else.
# On Ubuntu
/etc/ssl/certs/ca-certificates.crt should be used, for example.
# My
shortcut has been to use ‘locate ca-bundle.crt’ and use which ever one I think
is good ;)
tls_trust_file /etc/pki/tls/certs/ca-bundle.crt
logfile
~/.msmtp.log
# My email service
account gmail
host smtp.gmail.com
port 587
#NOTE: if you are using your corporate email ID and have
configured gmail -> provide that below
from some.user.name@gmail.com
auth on
#The following IS your gmail ID and password
user
some.user.name@gmail.com
password my-secret
# Set a default account
account default : gmail

The example here is for a Gmail account, but can easily be changed to use the local SMTP server as well.

Step 4: Now, by giving the full path name to the msmtp program as smtp server to git-send-email, you can send the patches through gmail or some other smtp account with TLS and/or user authentication.
git-send-email --smtp-server /usr/bin/msmtp
An alternative to setting --smtp-server each time is to set the global sendemail.smtpserver value.
git-config --global sendemail.smtpserver /usr/bin/msmtp
Another option is to configure a local smtp server on your machine, using a well-known SMTP server as smarthost. Then, all applications using localhost as a mail server (e.g. /usr/bin/mail) will work.

NOTE: On OS X with macports, msmtp can be installed with 'sudo port install msmtp', and '/usr/share/curl/curl-ca-bundle.crt' should work for tls_trust_file.
And your email forwarding system is setup:)