I haven't used the SMTP security servers, but I know a bit about email in general and 
exchange 5.5 in particular.  Are these relaying prohibited messages coming from your 
server, or the recipient server?  It's probably the later, which may indicate there's 
no reverse DNS entry associating your domain with the IP your firewall is running the 
SMTP security server on.

I hope this doesn't sound too 'baby talk' but I like to practice explaining things in 
simple terms, it helps me confirm my understanding of things and is good practice for 
dealing with users.

For example, in a typical SMTP session it'd look something like this;
Source server -=> destination server

The source server connects, advetises itself to the destination: "Hello, I'm 
mail.xxx.com".
Some destination servers if they're setup securely will then do a reverse dns lookup 
and compare the result the domain the server claims to be: "I see your ip address is 
10.10.10.243.  DNS agrees you are mail.xxx.com, so go ahead and send"
If the reverse DNS fails, the message will be kicked since the server can't confirm 
the source server is authoritative for that domain.

Now, since the security server is in play, it functions as an SMTP proxy;
source server -=> firewall -=> destination server

So, the destination server will see the session coming from the firewall, and thus the 
firewall needs to have a reverse DNS entry.

Hope this helps!

-----Original Message-----
From: Joven Guevarra [mailto:fatal_x@;YAHOO.COM]
Sent: Tuesday, November 12, 2002 7:51 PM
To: [EMAIL PROTECTED]
Subject: [FW-1] SMTP Security Problem


Hi to all,

I have an Exchange 5.5 Server. Then I setup my SMTP
Resource on our FW-1 to avoid spamming or relaying.
Then I encountered problems like "mailbox unavailable"
-> if i am sending from yahoo to our domain, or
"Relaying is Prohibited" -> if I am sending mails
outside.

this is my setup:

---------         - - -
exchange |       |      |
   5.5   |-----> | FW-1 |-----> Router Gateway
10.4.2.10|        - - -
---------

I used FW-1 to define a Static NAT for my Mail Server
from 10.4.2.10 it becomes a public ip.

This is my rule:

any ---> mail Server  -----> SMPT Resource --> accept
         outside interface
         (public ip)


why is it that I am encountering these problems? How
can I make it run right?

Thank You


Your Help is very much appreciated,
JGuevarra

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