RE: Relay Server -- MIDRANGE-L

Zak,

Is this at G1? Your public MX is an exchange box, so if that box is
forwarding to your iSeries make sure relay is turned off in the exchange
box. Also, if that box is forwarding then there is no reason for the outside
world to talk to the iSeries on port 25 at all, so close it in the firewall.

If this isn't at G1 then, no you cannot close the port on the firewall. All
inbound mail comes in to port 25. Part of the SMTP protocol is a rcpt to
command. A good conversation would be:
HELO sendingdomain.com
MAIL FROM: <sender@domain.com>
RCPT TO: <goodguy@yourdomain.com>
...

A relay would be:
HELO probablyfakesendingdomain.com
MAIL FROM: <probablyinvalid@nowhere.com>
RCPT TO: <poorspamreceipent@someotherdomain.com>

In the second case your iSeries happily "helps" the SPAMer by sending the
mail off to someotherdomain.com. Since both valid and relay mail use the
same port you can't stop it at a firewall.

You could install a SMTP gateway in the mix and block relaying on it, that
would also allow you to run some virus scanning software for your e-mails,
but as you pointed out there is relay protection on the iSeries too. Does
that protection go back to V4R2?

-Walden

------------
Walden H Leverich III
President
Tech Software
(516) 627-3800 x11
(208) 692-3308 eFax
WaldenL@TechSoftInc.com
http://www.TechSoftInc.com

Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)



-----Original Message-----
From: Metz, Zak [mailto:Zak_Metz@G1.com]
Sent: Friday, July 26, 2002 11:35
To: 'midrange-l@midrange.com'
Subject: RE: Relay Server


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Done, and tried some variations, but as soon as I start SMTP it starts
chewing away again.

Subsystem/Job  User        Type  CPU %  Function        Status
  QTSMTPSRVR   QTCP        BCH    54.2  PGM-QTMSSRCP     RUN
  QTGTELNETS   QTCP        BCH      .2                   DEQA
  QTSMTPCLNT   QTCP        BCH    20.7  PGM-QTMSCLCP     SELW
  QPADEV0004   ZAK         INT     4.8  CMD-WAJ          RUN
  DEFAULT      QTMHHTTP    BCI     3.4                   DEQW
  DEFAULT      QTMHHTTP    BCI      .4                   SIGW
  DEFAULT      QTMHHTTP    BCH      .4  PGM-QTMHHTTP     RUN

I kinda get the feeling that the data area isn't working.

Let me take this from another angle. I have a firewall/router. I should
never have anyone outside the firewall sending outgoing mail through the
AS/400. Can I close a port without preventing legit e-mail from coming in?

-----Original Message-----
From: Sean Porterfield [mailto:sporter@bestdist.com]
Sent: Friday, July 26, 2002 11:21 AM
To: midrange-l@midrange.com
Subject: RE: Relay Server


>-----Original Message-----
>From: Metz, Zak

>I'm at r420. I created the QUSRSYS/QTMSNORLY data area to deny
>spammers, but it looks like someone is using my system for just that
>right now. How can I blow away all mail in the process of being sent?
>This is a tiny system so I'm not concerned about accidentally blowing
>away real mail. Thanks!

IIRC:

 ENDMSF
 ENDTCPSVR *SMTP
 STRTCPSVR *SMTP
 STRMSF *CLEAR

But I may have the order wrong.

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