Explanations of SENDMAIL, SMTP, MAILX

[abhay_6]

Hi,

I have a few questions on mail protocols and programs :

1. Does Sendmail uses SMTP ? If not, then what protocol it uses.

2. How about MAILX ? Is it a protcol or does it runs on top of a protocol ?

3. I hear that SENDMAIL has security flaws ? What are those.


I understand SMTP is a

[John Dvorchak]

1. Sendmail uses SMTP.
2. Mailx can be considered a "font end" for sendmail. Similar to elm, pine etc. As such also uses SMTP.
3. The only security flaws that I am aware of is when sendmail is used as a daemon for sending and receiving email. It has been patched and is considered secure if you use the new versions and keep it patched. If you don't have a requirement to receive email then you don't have to run sendmail as a daemon and can just invoke it from the command line i.e.

cat some_file|sendmail jd123@nowher.com

Good luck.

[Ted Ellis_2]

I will just tack on 2 cents worth for security. There are numerous security holes in sendmail.. several new significant ones in the last 2 months were uncovered. If the unix servers do not need to act as mail servers or relays (most don't), then stop the daemon from running. modify parameter in /etc/rc.config.d/mailsrvs to not start sendmail process on reboot. There are other ways to do it, but not running this process, which is running on a default installation, will tighten the server up.