But if you set it for no relay, and only allow authenticated users, then
you are breaking the RFC. It would be better, and easier on the user, to
only allow relay for local users. And use Declude Junk Mail.
John Tolmachoff, Network Engineer
211 E. Imperial Hwy., Suite 106
Fullerton, CA� 92835
714-578-7999, ext. 104
[EMAIL PROTECTED]
www.reliancesoft.com
�
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]] On Behalf Of Joe Weirather
Sent: Thursday, August 30, 2001 8:54 PM
To: [EMAIL PROTECTED]
Subject: Re: [IMail Forum] Relaying mail
Murray-
Relay mail is designed to allow users (external to your local network)
to
send mail through your servers. You can see how this can become a
problem
if your servers are not properly configured or protected. If you
disable
relay, but set the mail CLIENTS to "auth" outgoing mail, the sessions
are
treated as though they ARE local and so the mail is sent. Anyone
without a
username and PW is SOL. Anyone with a username and PW can send mail
perfectly.
If you don't lock down your server it *will* be discovered by spammers
and
used to send spam. It's that simple. I didn't think it would happen to
me,
as I only host a few domains, but within 2 weeks my servers were
spamming/DOSing another domain (sorry Ed@Marlin). The only real
solution
I've found (aside from the wonderful 3rd party plug in products for
IMail)
is to disable relay all together, and set the mail clients to auth for
outgoing mail. It's an easy option to set and can prevent numerous
disasters.
If you don't believe me, leave your relay open for a week or two and
check
your logs daily. You should check your logs daily anyway, but pay close
attention to the file sizes of the logs- I ***GUARANTEE*** that if you
leave relay open, within 30 days the size of the log files will grow
exponentially as your IP/mail server name is spread among the spammers.
There are people out there whose time is dedicated exclusively to
finding
mail servers that aren't protected. It's only a matter of time before
your
server's ports are scanned and test mails are sent out by these people.
My advice (which solved the problem for me) is to disable all relay and
set
the clients to auth for outgoing.
Joe Weirather
[EMAIL PROTECTED]
----- Original Message -----
From: "Murray Gray" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, August 30, 2001 10:28 AM
Subject: [IMail Forum] Relaying mail
> Hi all,
>
> Please forgive the extra-newbie post...
>
> But i'm wondering whether someone can
> explain the implications of the 'Relay Mail'
> option.
>
> How useful is the feature, when would you
> use it - and how do you stop it being abused?
>
> Best regards,
>
> Murray.
>
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