SendMail and open relay

Hi,
Sorry, I am new to Linux and sendmail. I went to http://aboutmydns.com and
ran their quick test. It complains that my sendmail is an open relay, which
is very likely. How do I close it. I still want my Internal users to send
out emails.

Thanks.

Jerry Baker wrote:

> Sorry, I am new to Linux and sendmail. I went to http://aboutmydns.com and
> ran their quick test. It complains that my sendmail is an open relay, which
> is very likely. How do I close it. I still want my Internal users to send
> out emails.

The default configuration doesn't do that, so what did you change?
See cf/README.

Please post two logfile entries (from=/to=) of a relayed mail
that show the problem. If you don't want to post real data here,
contact sendmail.org.

Include your .mc (not .cf) file and the output of

echo '$=R' | sendmail -bt -d0.10

--
A: Maybe because some people are too annoyed by top-posting.
Q: Why do I not get an answer to my question(s)?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

Jerry;

I'm assuming that you have a standard install from a distibution like
Fedora or Red Hat. Check that your access file (mine is in /etc/mail)
looks something like this and no more:

localhost.localdomain RELAY
localhost RELAY
127.0.0.1 RELAY

# internal net
10.1.9 RELAY

Where my internal net is 10.1.9.0/24

Check that your local-host-names file has something like this:

# hosts that you receive mail for
localhost
yourdomain.com

Also make sure that you have this line in sednmail.cf to make sendmail
accessible (this assumes you want to receive mail from outside):

O DaemonPortOptions=Port=smtp,Addr=0.0.0.0, Name=MTA

(Fedora has 127.0.0.1 as the default)

Be sure to restart sendmail after making changes.

Also make sure that if this server runs apache you do not have the
ProxyPass directive enabled. I had a month during which spammers were
using that hole to access sendmail and spam.

> Hi,
> Sorry, I am new to Linux and sendmail. I went to http://aboutmydns.com and
> ran their quick test. It complains that my sendmail is an open relay, which
> is very likely. How do I close it. I still want my Internal users to send
> out emails.
>
> Thanks.

Jerry,

We want to help, but a word of etiquette - please don't cross-post

Diggy

On 30 Sep 2004 19:31:43 -0700, (E-Mail Removed) (miguelk)
wrote:

>Jerry;
>
>I'm assuming that you have a standard install from a distibution like
>Fedora or Red Hat. Check that your access file (mine is in /etc/mail)
>looks something like this and no more:
>
>localhost.localdomain RELAY
>localhost RELAY
>127.0.0.1 RELAY
>
># internal net
>10.1.9 RELAY
>
>Where my internal net is 10.1.9.0/24
>
>Check that your local-host-names file has something like this:
>
># hosts that you receive mail for
>localhost
>yourdomain.com
>
>Also make sure that you have this line in sednmail.cf to make sendmail
>accessible (this assumes you want to receive mail from outside):
>
>O DaemonPortOptions=Port=smtp,Addr=0.0.0.0, Name=MTA
>
>(Fedora has 127.0.0.1 as the default)
>
>Be sure to restart sendmail after making changes.
>
>Also make sure that if this server runs apache you do not have the
>ProxyPass directive enabled. I had a month during which spammers were
>using that hole to access sendmail and spam.
>
>> Hi,
>> Sorry, I am new to Linux and sendmail. I went to http://aboutmydns.com and
>> ran their quick test. It complains that my sendmail is an open relay, which
>> is very likely. How do I close it. I still want my Internal users to send
>> out emails.
>>
>> Thanks.

Diggy <(E-Mail Removed)> wrote:
> We want to help, but a word of etiquette - please don't cross-post

Crossposting is perfectly acceptable, provided the groups are
relevant. Multiposting is not acceptable under any circumstances.

This message appears to have been correctly crossposted. Good for you,
poster.

Chris