[MAILX ERROR: STATUS=BOUNCED] Fixing Mailx error when sending emails from Command line

Mailx is an intelligent mail processing system, which has a command syntax reminiscent of ed(1) with lines replaced by messages. It is based on Berkeley Mail 8.1, is intended to provide the functionality of the POSIX mailx command, and offers extensions for MIME, IMAP, POP3, SMTP, and S/MIME. Mailx provides enhanced features for interactive use, such as caching and disconnected operation for IMAP, message threading, scoring, and filtering. It is also usable as a mail batch language, both for sending and receiving mail. While trying to send an email from CLI on a local server to an external email address, you can come across the error log below.

echo -e "testing email via yourisp.com from command line\n\nsent on: $(date)" | mailx -r "Test-Email <ola@testlab.com>" -s "test cli email $(date)" -- meettoy2004@gmail.com

To fix this, make sure you have the SMTP server address (either Gmail or your ISP) and also authentication to log in (Some ISP’s allow anonymous) then use the command below

echo "This is a test email on CLI initiated using mailx" | mailx -vvv -s "Test mail" -r "ola@testlab.com" -S smtp="your smtp server address" meettoy2004@gmail.com

USING GMAIL AS THE EMAIL SERVER
– Create a certificate directory then create new certificate and key databases

mkdir ~/.certs

certutil -N -d ~/.certs

echo -n | openssl s_client -connect smtp.gmail.com:465 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > ~/.certs/gmail.crt

certutil -A -n "Google Internet Authority" -t "C,," -d ~/.certs -i ~/.certs/gmail.crt

Add configurations into the mailx config file (/etc/mail.rc)

 
account gmail {
set smtp-use-starttls
set ssl-verify=ignore
set smtp-auth=login
set smtp=smtp://smtp.gmail.com:587
set from="username@gmail.com"
set smtp-auth-user=username@gmail.com
set smtp-auth-password=jjdeuen@SGY^
set ssl-verify=ignore
set nss-config-dir=/home/path/to/.certs
}

echo -e " body " | mailx -A gmail -s "Subject" recipient@anywhere.com

I hope you found this blog post helpful. If you have any questions, please let me know in the comment session.