RE: can a virus do this?

  • From: "Craig Haywood" <craig@xxxxxxxxxxxxxx>
  • To: "'[ExchangeList]'" <exchangelist@xxxxxxxxxxxxx>
  • Date: Tue, 19 Aug 2003 23:03:31 +0200

I think you r misunderstanding me.  let's say you host mail for
alias@xxxxxxx, alias@xxxxxxx and your exchage domain is, then
exchange would automatically be configured to accept mail on behalf of  However, you must then specify that mail may be relayed to
and  You don't have to specify domains for people who may send to
these domains. I support a small isp, and this how we do it. The server is
completely closed for relays.
for our email users, they can send to any domain as long as they r
authenticated. poeple sending mail to them obviously don't authenticate, so
we tell exchange it is okay to relay mail to these domains (We're hosting +-
150 domains) so that users who have domains registered with the isp can
receive mail at user@their 


From: David Liles [mailto:dliles@xxxxxxxxxxxx] 
Sent: 19 August 2003 09:35 PM
To: [ExchangeList]
Subject: [exchangelist] RE: can a virus do this?

To the best of my knowledge, there shouldn't be any relaying.....
The email account that is erroring is on our exchange server so nothing
should be passing through our SMTP service. Our server is the end point in
the process.... I'm currently using an external email account to test by
sending an email to my account on our new exchange server.
If we need to specify external domains that can relay just so we can receive
email it seems we would be turnning ourself into an open relay....

-----Original Message----- 
From: Craig Haywood [mailto:craig@xxxxxxxxxxxxxx] 
Sent: Tue 8/19/2003 3:29 PM 
To: [ExchangeList] 
Subject: [exchangelist] RE: can a virus do this?

I take it, when you send mail internally, you have the option to relay for
authenticated users ticked. However, external users don't authenticate. On
your internet mail smtp connector, you need to specify domains which may
relay through your server.
Hope this helps


From: David Liles [mailto:dliles@xxxxxxxxxxxx] 
Sent: 19 August 2003 08:52 PM
To: [ExchangeList]
Subject: [exchangelist] can a virus do this?

Can a virus cause this?
We have one Exchange 2000 server we are trying to replace that is currently
exposed (public IP - this is bad... we know).
We have just added a new Exchange 2000 server that is on a private IP and
behind an MS ISA firewall only box.
We have only migrated a couple of email accounts from the old Exchange
server to the new one for testing and are experiencing problems when sending
to those accounts.
We can send internally to any email account without problem, as well as send
mail externally without problem.
We are unable to send mail to any of the users that we migrated to the new
Exchange server from an external email account (fyi... this email address is
external), when we try we get the following error:
Your message did not reach some or all of the intended recipients. 

  Subject: FW: Welcome to the Discussion List 
  Sent: 8/19/2003 9:33 AM 

The following recipient(s) could not be reached: 

  dave@xxxxxxxxxxxxxxxxxxx on 8/19/2003 9:33 AM
  You do not have permission to send to this recipient. For assistance,
contact your system administrator.
  < #5.7.1 smtp;550 5.7.1 Unable to relay for
ISA configuration:
We have published our Exchange server using the Secure Mail Server
publishing wizard.
Users are able to access the internet.
Protocol Rules allow for DNS Query and DNS Zone Transfers and SMTP to travel
IP Packet Filters configured for SMTP inbound and SMTP outboud (individual
filter entries)
Other configuration info:
The Exchange server has a private IP and is configured with DNS services.
The NIC DNS entry points to itself and the DNS service is configured to
forward to our ISP's DNS server.
The default gate way is the private IP of the ISA box.
The recipient policy used for the user accounts having problems is the
default for our domain.
Any ideas why we are having his problem?
Thanks - Dave

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