RE: Open Mail Relay - Exchange 5.0

  • From: "Thomas Brennan" <tbrennan@xxxxxxxxxxxxx>
  • To: "'[ExchangeList]'" <exchangelist@xxxxxxxxxxxxx>
  • Date: Fri, 10 May 2002 10:27:43 -0400



Thomas Brennan
Federated Systems Group
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-----Original Message-----
From: Richard Pettigrew [mailto:Richard@xxxxxxxxxxx] 
Sent: Friday, May 10, 2002 9:40 AM
To: [ExchangeList]
Subject: [exchangelist] Open Mail Relay - Exchange 5.0

Hi there, I need some advice on closing and open mail relay.

The difficulty I am facing is that it is Exchange version 5.

The server in question is an old SBS 4.0 server.

The setup is as follows:

Single server with one netcard.
Private IP Address 10.x.x.x range
Cisco801 router on - router is using NAT

My question is this; how do i configure Exch 5 to only allow specified
smtp server ip's to connect to it? But if the NAT on the router
translates all incomming addresses on port 25 then surely the exchange
server will only ever see the originating address connecting to it as
that of router's internal address.

If this is the case, then should I bee looking at getting a hardware
firewall? (as well as obviously upgrading the exchange server!)

all comments gratefully appreciated.

Richard Pettigrew
Harkins & Anderson Ltd

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