How do I send mail from Tripwire using SMTP?

Question

I have just installed tripwire using Ubuntu repos and have gone into the configuration files and changed everything to what I want. When in comes to the options for SMTP mail method and the server and port to use, I am stumped. When I run the test email I get this error message.

/usr/sbin/tripwire --test --email blah@nowhere
Sending a test message to: blah@nowhere
### Error: The SMTP connection could not be established.
### Server: localhost
### Exiting...
Email test failed.

I have made appropriate changes to the firewall. I don't have an smtp server installed. Do I need to? Any other ways I could use without installing an SMTP server due to security issues?

Solution

If your hostname on your server is not a FQDN (fully qualified domain name - i.e. myhost vs. myhost.example.com, where the latter is a FQDN) you will probably not be able to send out emails with tripwire. This was the case for me using Ubuntu server.

You can check your hostname with:

hostname

And you can change it with:

sudo hostname MYFQDN

where MYFQDN is your new FQDN hostname.

After this you should run a tripwire check:

sudo tripwire --check

You should see various errors now. Tripwire uses HOSTNAME to name various files. You will need to rename a few.

Finally you will also need to reinitialize your database due to the error:

Policy file does not match policy used to create database.

You can do that with:

sudo tripwire -m i

And it should now work.

EDIT: Two additional comments...

1. to permanently change my hostname I had to edit /etc/hostname otherwise your changes will not survive a reboot

2. you may be able to update your database above (instead of using sudo tripwire -m i) by using:

   sudo tripwire -m p