Sendmail alias question

[Bill Watson]

Kurt,
Thank you for your thorough reply! I was worried that I was too vague and it
appears that I was. Here is the scene that I want to "fix":

joe at here.com sends an email "To" grouplist at here.com instead of "BCC"ing
grouplist at here.com and this causes everyone on grouplist to be able to see
that the email was sent to grouplist at here.com.  ALSO this means that
everyone with spy/virus infected email software on grouplist also has now
notified the evil spy folks that grouplist at here.com is a valid email
address. Then the evildoer spy folks now know to send from everywhere on the
planet to grouplist at here.com all their evil messages. This means that if
grouplist is all our outside employees for instance, then everybody in that
group gets evil messages with the spy folks only sending one email.

Now if only folks within our walls were able to use grouplist at here.com and
everyone outside our walls got a 505 invalid user message, then I could
better control the evildoers being able to send stuff to grouplist@ from all
their "owned" PC base.

I just don't know how to restrict grouplist@ from being a valid name to
outsiders.

Thanks,
Bill Watson
bill at magicdigits.com


-----Original Message-----
From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of
pbdlists at pinboard.com
Sent: Thursday, November 12, 2009 12:00 PM
To: redhat-sysadmin-list at redhat.com
Subject: Re: Sendmail alias question

Hi Bill,

The alias will simply be expanded to everything after the key, so your
example expands to "me" "you" "them" "us" "yall" whatever that might be.
These can be local users, lists, remote addresses or further groups. If
you want to restrict it to "me at local.domain" and "you at local.domain" and
"them at remote.domain" then
it should look like

folks: me at local.domain,you at local.domain,them at remote.domain

The aliases file works just like a translation: folks is translated to
exactly the list that follows. Your local sendmail then interprets that
list just as if those addresses were given as the recipients (an as
already mentioned, if one of those alias destinations is another alias,
that gets expanded again).

Maybe you want to have a look at
http://www.bga.org/~lessem/psyc5112/usail/mail/aliasing/

Hope this helps somewhat.

Cheers,

Kurt


On Mon, Nov 09, 2009 at 02:51:18PM -0800, Bill Watson wrote:
> This is probably too far off topic for this list, but hopefully someone
will take pity on me and help out. I have tried googling a bunch of times
and either get 10,000 off topic answers or none. 
> 
> When using /etc/aliases to expand a user group such as
> 
> folks:  me, you, them, us, yall
> 
> this seems to work wonderfully. Unfortunately a little too wonderfully.
> 
> What is the easiest (if any) way to restrict this alias group to
> 
> 1) folks on the same subnet (internal use only) - localhost/etc
> or
> 2) folks at least claiming to be of a certain domain (mydomain.com)
> 
> I have found that if we fail to BCC the sent mail, then the spammers pick
up the group name and then their junk gets replicated with great efficiency.
The restrictions would try to help reduce the junk mail.
> 
> Thank you in advance,
> 
> Bill Watson

--
redhat-sysadmin-list mailing list
redhat-sysadmin-list at redhat.com
https://www.redhat.com/mailman/listinfo/redhat-sysadmin-list