If you deal with mail-server setup and administration, you will fall in love with swaks
I like swaks because it make testing many things easy e.g. email delivery, SMTP server, GTUBE spam test, EICAR virus test, attachment test, gmail smtp test. Also it makes finding non-verifiable emails easy from list of email addresses.
One more thing I like about swaks is automatically create subject and body content. Subject line is set to date & time which is again useful while debugging.
Installation
On Ubuntu
apt-get install swaks
On Mac
brew install swaks
Usage
Sending a test mail via localhost
swaks --to user@example.com
You can simply run swaks without any parameter as well.
When run without any parameter, it will use localhost/sendmail program as SMTP server and prompt for to email address.
Note: When you use your local machine, please make sure to check spam/junk folder on destination mail server.
Sending a test mail using any SMTP server
If your localhost cannot send mail, you can specify a reliable SMTP server using:
swaks --to user@example.com --server smtp.example.com
If smtp.example.com accepts your mail, a case of open-relay, your mail will be through. Or you will see error/reason for not sending mail in output.
Sending a test mail using Gmail’s SMTP server
swaks -t user@example.com -s smtp.gmail.com:587 -tls -a LOGIN
Above will prompt your gmail username and password. Mail will be delivered from authenticated Gmail account. You can verify this by checking your Gmail’s sent folder! 😉
Send EICAR Virus Test Email
Test a virus scanner using EICAR in an attachment. Don’t show the message DATA part.
swaks -t user@example.com --attach --suppress-data < /path/to/eicar.txt
--attach switch can be used to specify attachment.
Send GTUBE Spam Test Email
Test a spam scanner using GTUBE in the body of an email.
swaks --to user@example.com --body /path/to/gtube/file
Test List of Fake Email Addressees
Report all the recipients in a text file that are non-verifiable:
for E in `cat /path/to/email/file`
do
swaks --to $E --server test-server.example.com --quit-after RCPT --hide-all
[ $? -ne 0 ] && echo $E
done
Credits: man swaks for most examples!