topic Re: SMTP Services in Operating System - Linux

SMTP Services

Edwin Ruiz_2 — Tue, 24 Feb 2004 16:32:40 GMT

How can i know if my Red Hat linux Server 7.2 has the SMTP services enable?

Re: SMTP Services

Martin P.J. Zinser — Tue, 24 Feb 2004 16:45:12 GMT

Hello Edwin,

the easiest will be (assuming you are logged in to this server)

telnet 127.0.0.1 25

If you can connect and talk to port 25 you have an SMTP server listening.

Else /etc/[x]inted.conf should contain the information if the service is supposed to be started and which software you want to run.

Greetings, Martin

Re: SMTP Services

Stuart Browne — Tue, 24 Feb 2004 17:23:07 GMT

If it's been turned off however, you might want to test for the existance of an SMTP server, like:

rpm -q sendmail postfix

These are the two main SMTP services that are installed on a standard RH box. On a RH7.2 box, it'll be sendmail by default.

If you want to use it just for your local machine, just starting it should be sufficient (if it isn't already):

service sendmail start
chkconfig sendmail on

The second command will make it start after a reboot.

If you want SMTP to be open to the world however, you'll need to make some changes to the configuration, after updating sendmail to the latest version using up2date or pulling the updated RPM's yourself from ftp.redhat.com/pub/redhat/updates/7.2/en/os/i386/sendmail* (or from your favourite mirror).

Once that is done, you'll need to modify the /etc/mail/sendmail.mc, commenting out the DaemonPortOptions line.

Sendmail config is a beast though.. Get back to us if you need more details.

NOTE: www.tldp.org is your friend ;)

Re: SMTP Services

Steven E. Protter — Tue, 24 Feb 2004 17:35:33 GMT

sendmail is installed in Red Hat Linux unless you go out of your way to exclude it.

To run it as a deamon

chkconfig --level 12345 sendmail on

If the server is exposed to the Internet it is vulnerable to use as a smtp relay server.

It is very important to take the following basic steps after activation.

Makes sure there are no servers set for relay in /etc/mail/access

If you are doing virtual domain hosting have no entries in /etc/aliases, /etc/mail/virtusertable /etc/mail/genericstable with the @domainname.com entry.

This will let someone connect to your server on port 25 and send mail to anyone on the domain and cc hundreds of people.

Its a lot of work to secure an smtp server. Once complete, it does prove to be a very robust tools.

Take a look at recent sendmail threads. You will find them interesting.

SEP

Re: SMTP Services

Edwin Ruiz_2 — Wed, 25 Feb 2004 09:12:58 GMT

Ok Thanks all!

Now.. i want to configure my sendmail for send email to other sites on my domain. i use sendmail edruiz@taca.com but messages are missing. want changes can i do?

Pls help me

Re: SMTP Services

Don_89 — Thu, 26 Feb 2004 08:28:05 GMT

Sendmail is a complete beast to learn. If you want a more secure and much easier SMTP server to use, I would recommend Qmail. Its the second in popularity to sendmail and it is very well supported..

www.qmail.org