Is the SMTP safe?

[Kira]

Hi,

I just found out I can connect to my SMTP Server via pythons smtplib without the need to login and send mails to whatever address with a random 'from'-address.

I did some relay tests online and they all say it's relay safe.. but... is it a correct behaviour?

As an example:

smpt = smptllib.SMTP('myServer.de')
smpt.sendmail('bla@blubb.com', 'someone@somewhere.de', '....;)
smpt.quit()

This works, and I am doing this from remote, not locally on my Server.

Kira

[till]

Yes, thats the correct behaviour.

There are 3 possibilitys where every mailserver ahs to accept emails:

1) The email is from localhost
2) The email is sent from a server that we allow to relay. See mynetworks setting in main.cf
3) The recipient domain is a local domain of this server.

[Kira]

Hi,

thanks for your answer.

I did the test above from my machine at work.
None of the 3 points you mentioned match this machine - I think.

So is this realy correct?

Thanks,
Kira

[till]

Use this test to find out if your machine relays:

http://www.abuse.net/relay.html

Leave the email field empty or use a external address like gmail.

If you followed the perfect setup guide to install your server, then it is no open relay.

[Kira]

Okay, seems to be safe..
Though I don't understand why I can do what I described above..

Thanks a lot,
Kira