Generate RFC822 compliant e-mail messages for tests and send it over SMTP.
While it's easy to send test messages like echo asdf | mail you@gmail.com
or via telnet mx.example.com 25
I need a tool which:
- Generates valid messages
- Messages should not look spammy or very suspicious
- Easy to use and repeat test
- Ability to customize messages
- Work well with msmtp or other full-featured SMTP client (e.g. which can send over secure SMTP connection with authentication)
- Support DKIM signatures
pip3 install testmsg
or
pipx install testmsg
Just generate minimal valid message, print to stdout (not sending).
$ testmsg --to you@gmail.com --lorem
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Subject: Sent with github.com/yaroslaff/testmsg
From: from@example.com
To: you@gmail.com
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempo=
r incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut al=
iquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore =
eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia des=
erunt mollit anim id est laborum.
You can pass options either as command-line arguments or in .env
file. Example:
FROM=noreply@example.com
TO=me@example.net
SUBJECT="My subj"
# Only one of next three is possible at same time
# TEXT="Hello, world!"
# MSG=/tmp/helloworld.txt
LOREM=1
# add timestamp to message body
TIMESTAMP=1
# if we want to send message, set mailserver host there. Otherwise testmsg will just print to stdout
SEND=localhost
# You may override port (e.g. 587)
# PORT=25
# SMTP authentication
# If SMTPPASS given, will use SMTP authentication. Default SMTPUSER is same as FROM
# SMTPUSER=aaa@bbb.com
SMTPPASS="MySecretPassword"
# DKIM (very very optional)
# DKIM_SELECTOR="mail"
# DKIM_PRIVKEY=/etc/ssl/private/test.example.com.pem
VERBOSE=1
To enable boolean option use value "1", to disable - any other value.
With such .env file, you can send message with just testmsg
command (no options).
To actually send message via SMTP server add --send localhost
and optionally add -v
for verbosity.
testmsg -v --lorem --from you@example.net --to you@gmail.com --send localhost
See below about how to use authentication and SSL/TLS and how to use with msmtp
(or other smtp clients).
Use --from
, --to
and --subject
to override basic properties of message, use --add HEADER VALUE
to add custom header(s).
Default message text is empty, use --text "blah blah blah"
or --lorem
or --msg PATH
or --msg -
.(to read from stdin). Add --time
to add current time as an prefix to text.
Use --attachment
(or --att
) to add attachments: --att FILE1 FILE2 ...
Generate DKIM RSA keys:
# generate private RSA key for DKIM
openssl genrsa -out example.com.pem 1024
# generate public key for DKIM
openssl rsa -in example.com.pem -out example.com.pub -pubout
Make DKIM DNS record with as SELECTOR
._domainkey.example.com and verify it (here I decide to use selector mail
):
$ host -t txt mail._domainkey.example.com
mail._domainkey.example.com.net descriptive text "v=DKIM1; h=sha256; k=rsa; p=MII...."
send DKIM signed message to gmail or mail-tester.com! Use --selector
and --privkey
arguments.
testmsg -f test@example.com -t mailbox@gmail.com --lorem --selector mail --privkey example.com.pem -v --send localhost
To use authentication, use --user
and --password
(or --pass
) parameters. Use --ssl
to use SSL-capable SMTP server (port 465), or use --starttls
to use STARTTLS
SMTP command. If neither --ssl
nor --starttls
is given, message and authentication credentials are sent over plain unencrypted connection, which is highly insecure.
If --user
is not given (but --password
given), testmsg will use username same as from (--from
/ -f
) address.
Example:
testmsg -v -f test1@example.com -t somebody@example.net --lorem --pass "MyTestPass" --send mx.example.com --starttls
Here we send with TLS and authentication (using msmtp). Username for authentication (--user
) is same as FROM address. Testmsg generates valid message and msmtp sends it.
FROM=sender@example.com
TO=recipient@gmail.com
testmsg -f $FROM -t $TO --lorem | msmtp -v --host smtp.office365.com --port 587 --user $FROM --passwordeval='echo MyTestPass' -f $FROM --tls=on --auth=on $TO