There will always be people too stupid not to use POP3 as well.  What
can you say.  POP3 is an unsecure and unsecurable protocol without
adding something else.

You can use multiple interfaces and have your POP clients connect
differently.  You can allow relaying only if they first set up a VPN
connection and authenticate to send relaying SMTP then.

Perhaps deeper technical knowledge would help you solve this problem.
Perhaps asking someone who specializes in Exchange could have helped you
with this over the years.

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Greg Deckler
Sent: Friday, December 12, 2003 11:00 AM
To: Exchange Discussions
Subject: RE: Mail Processing by Exchange vs. SendMail

Yes, you were lucky. I have seen this exact scenario happen a couple
times
now. Fydora or whoever apparently did not understand this scenario but
it
is a fairly common scenario in small office environments with people on
the road connecting their laptops to hotel networks and the like. Yes,
OWA
is available, but there are lots of people in this world that are always
going to hate something like OWA. OWA in 2003 is pretty sweet, I must
say,
but there will always be people that don't like.

> It's been a while since I've supported POP3 clients on Exchange (5.5)
but,
> as I recall, I had no issues with anonymous relaying.  I believe that
> Exchange 5.5 allowed anonymous SMTP inbound connections (that is,
> connections for mail to be delivered locally) and would allow relaying
by
> authenticated users only.
> 
> Or maybe I was just luckily that the spammers different find this
server?
> 
> Aaron
> 
> -----Original Message-----
> From: Greg Deckler [mailto:[EMAIL PROTECTED] 
> Sent: Friday, December 12, 2003 11:30 AM
> To: Exchange Discussions
> Subject: RE: Mail Processing by Exchange vs. SendMail
> 
> 
> While I am not sure that the "Greg" in this post was directed at me or
> whether this is some new form of abuse and sarcasm, it is pretty much
> irrelevant as I do have some things to say on this issue.
> 
> The biggest problem that I have had with Exchange on the outside of
the SMTP
> mail chain is anti-spam in a small office environment. It is not that
> anti-spam functionality does not exist in Exchange, but it is in its
native
> implementation. The issue actually revolves around POP3 users. For
your
> Exchange server to serve as the end-point for SMTP connections from
> anywhere, you generally have to turn on Anonymous Authentication. This
> allows any SMTP server to connect to yours to send email. Now, let's
say you
> have POP3 users that might be connecting from anywhere they please on
just
> about anyone's network. To allow these people to send email, you have
to
> generally turn go into Relay Restrictions and turn on "Allow all
computers
> which successfully authenticate to relay..." The problem with this is
that
> Anonymous Authentication is also on, so guess what? Spammers can
anonymously
> authenticate and relay spam, because, apparently in the Microsoft
world
> Anonymous Authentication is just as good as any other Authentication.
Oh
> well. And yes, you can turn this checkbox off and set up specific
computers,
> but if they are POP3 clients connecting from anywhere, you are hosed
there
> and if you set up this by domain, you have a whole other set of
problems,
> not the least of which is that this forces a reverse DNS lookup.
> 
> What really needs to happen with this is that Microsoft needs to
simply add
> a checkbox that says something along the lines of "Anonymous
Authentication
> can only send inbound messages and not relay." But, I guess since I am
not
> an MVP the likelihood of this happening is close to zero.
> 
> In terms of speed, I do not have hard numbers, but if you buddy is
making
> rash statements like you indicate, he or she does not either. Tell
your
> buddy to show you the proof or jump off a pier. You may want to be a
little
> more PC. I have only seen an Exchange server's SMTP mail engine under
duress
> when a spammer was involved and we are talking ungodly amounts of
messages
> with lots of failures and retries.
> 
> In terms of having Exchange exposed to the outside world, you can
secure it,
> put it in a DMZ and make it a front-end server. Again, the main issue
I have
> is with anti-spam in specific situations but if you don't have to
worry
> about POP3 users or have an extra box to point POP3 users to, then
you're
> good to go.
> 
> Finally, I will point out that *technically* you do not even need
Exchange
> as the SMTP engine is built into Windows 2000/2003 and I have played
around
> with using this to serve as a host to forward SMTP mail into my
Exchange
> environment. It's been awhile since I really sat down with it, but if
memory
> serves it worked just fine.
> 
> > > Greg, would you please help with this discussion on
SendMail....Your
> > > input will be highly regarded....Thanks
> > 
> > Tell him Postfix is more secure...  :P
> > > 
> > > Personally, I like to put another server at the edge for SMTP that

> > > is NOT Exchange when I can...
> > > 
> > > As far as who's faster at processing...  Who cares, can Sendmail
do
> > > calendaring, public folders, etc?
> > > 
> > > -----Original Message-----
> > > From: Sean Faust [mailto:[EMAIL PROTECTED]
> > > Sent: Friday, December 12, 2003 9:20 AM
> > > To: Exchange Discussions
> > > Subject: Mail Processing by Exchange vs. SendMail
> > > 
> > > Good Morning All,
> > > 
> > > I have a Unix/Linux admin that is just wearing me out with regards

> > > to Exchanging being 3rd rate.  Given all of the variables
including
> > > memory, processors, etc.  How much mail traffic can Exchange
process
> > > in an hour/day and what is the advantage if any of putting
SendMail
> > > in front of Exchange?
> > > 
> > > His last statement was that SendMail can process more mail in one 
> > > minute than Exchagne can process in a day.
> > > 
> > > Thanks,
> > > 
> > > Sean
> > > 
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