Databases, Systems & Networks

Send email notifications using Gmail SMTP

Using Gmail SMTP: Suppose you want to configure a Linux app to send out email messages from your server or desktop. The email messages can be part of email newsletters, status updates (e.g., Cachet), monitoring alerts (e.g., Monit), disk events (e.g., RAID mdadm), and so on. While you can set up your own outgoing mail server to deliver messages, you can alternatively rely on a freely available public SMTP server as a maintenance-free option.

One of the most reliable free SMTP servers is from Google’s Gmail service. All you have to do to send email notifications within your app is to add Gmail’s SMTP server address and your credentials to the app, and you are good to go.

One catch with using Gmail’s SMTP server is that there are various restrictions in place, mainly to combat spammers and email marketers who often abuse the server. For example, you can send messages to no more than 100 addresses at once, and no more than 500 recipients per day. Also, if you don’t want to be flagged as a spammer, you cannot send a large number of undeliverable messages. When any of these limitations is reached, your Gmail account will temporarily be locked out for a day. In short, Gmail’s SMTP server is perfectly fine for your personal use, but not meant for commercial bulk emails.

With that being said, let me demonstrate how to use Gmail’s SMTP server in Linux environment.

Google Gmail SMTP Server Setting

If you want to send emails from your app using Gmail’s SMTP server, you need to adjust the security setting of the Gmail account to be used. Go to the Google account settings, and enable the option to allow less secure apps, which is off by default.

Then you will need to provide your app with the following details.

• Outgoing mail server (SMTP server): smtp.gmail.com
• Use authentication: yes
• Use secure connection: yes
• Username: your Gmail account ID (e.g., “alice” if your email is alice@gmail.com)
• Password: your Gmail password
• Port: 587 (TLS) or 465 (SSL)

Exact configuration syntax may vary depending on apps. In the rest of this tutorial, I will show you several useful examples of using Gmail SMTP server in Linux.

Send Emails from the Command Line

As the first example, let’s try the most basic email functionality: send an email from the command line using Gmail SMTP server. For this, I am going to use a command-line email client called Mutt.

First, install Mutt as follows.

For Debian-based system:

$ sudo apt-get install mutt

For Red Hat based system:

$ sudo yum install mutt

Create a mutt configuration file (~/.muttrc) and specify in the file Gmail SMTP server information as follows. Replace <gmail-id> with your own Gmail ID. Note that this configuration is for sending emails only (not receiving emails).

$ vi ~/.muttrc

set from = "<gmail-id>@gmail.com"
set realname = "Dan Nanni"
set smtp_url = "smtp://<gmail-id>@smtp.gmail.com:587/"
set smtp_pass = "<gmail-password>"

Now you are ready to send out an email using mutt:

$ echo "This is an email body." | mutt -s "This is an email subject" alice@yahoo.com

To attach a file in an email, use “-a” option:

$ echo "This is an email body." | mutt -s "This is an email subject" alice@yahoo.com -a ~/test_attachment.jpg

Using Gmail SMTP server means that the emails appear as sent from your Gmail account. In other words, a recipient will see your Gmail address as the sender’s address. If you want to use your domain as the email sender, you need to use Gmail SMTP relay service instead.

Another note is that if you are concerned about placing your SMTP password in the plain-text .muttrc file, you can encrypt the password using GnuPG.

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source: deribin.com

Very simple solution:
1) add rule to /etc/fail2ban/jail.conf:

[spam]
enabled = true
filter = spam
action = iptables[name=SPAM, port=smtp, protocol=tcp]
sendmail-whois[name=SPAM, dest=email@your.doamin.com, sender=fail2ban@your.domain.com]
logpath = /var/log/mail.log
bantime = 3600
ignoreip = 127.0.0.1 xxx.xxx.xxx.xxx/xx
maxretry = 2


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Source: Gregory F. Welch

Adds “Copy to Recent,” “Move to Recent,” and “Go to Recent” menu items to Apple’s Mail application. These menu items contain dynamically-updated lists of recently used mailboxes. The number of mailboxes kept in the list is determined by the “Number of Recent Items” setting for Documents in the Appearance panel of the OS X System Preferences.

Usage

Once installed (see instructions below) as you drag or option-drag a message to a mailbox, that mailbox should then appear under

• “Copy to Recent” and “Move to Recent” submenus under the “Messages” menu, and
• a “Go to Recent” submenu under the “Mailboxes” menu.

Similarly if you use Mail’s built-in “Move To” or “Copy To” menus to move a message to a mailbox, that mailbox should then appear in the lists. The recent mailboxes will be sorted alphabetically, the same as OS X does for recent documents. (You can change the sorting behavior using the Terminal application as described below.)

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source: http://blog.dp.cx/25/postfix-fail2ban-win

Recently, I had to lease a new server. My old one was ok, but it was 5 years old, and showing it’s age. The most recent bout of problems was due to postfix, and a specific domain that I host mail for.

I had previously set up Policyd in an attempt to stop the influx of spam before it ever hit the server, but it wasn’t doing anything at this point. So approximately 800 messages per minute were getting directly to Postfix, and then running queries against MySQL (I use virtual maps for users, aliases, domains, etc). 99% of these messages were to non-existant users, so Postfix would bounce them. But the little 2.0GHz Celeron couldn’t handle it. The load shot up to 8 for around 3 weeks, and stayed there. I wish the fail2ban idea had come to me sooner… Lire la suite…