Re: Public IP as Relay?

From: Miha Pihler [MVP] (
Date: 11/21/05

  • Next message: Eduardo T: "Re: Public IP as Relay?"
    Date: Mon, 21 Nov 2005 20:43:50 +0100


    Since SMTP is running on same server as your application you could also
    enter as an IP address. This would only allow relaying from this
    local computer.

    If such configuration is dangerous depends on other configuration factors.
    E.g. are there any firewalls between unsafe networks (e.g. internet) and you
    server? If there are and if they block access to services on your server
    that should not be accessible to everyone on the internet, than that can add
    a lot to security of your server.

    Note: Windows 2003 server has built in Firewall. You can use this firewall
    if you don't have any other.

    Microsoft MVP - Windows Security
    "Eduardo T" <> wrote in message
    > Is it safe to use the public IP of a server as a relay in IIS? I'm
    > testing the SMTP server in IIS.   A web app on this server needs to be
    > able to send email.  The only way I've got it to work so far is by
    > going into Default SMTP Virtual Server Properties > Relay Restrictions
    >> selecting "Only the list below" and adding the public IP with access of 
    >> "Granted."
    > Is this safe?  Or is this something that can easily be exploited?  I
    > would think if it's only accepting relays that come from it's own IP,
    > this would work out, but I'm not sure.

  • Next message: Eduardo T: "Re: Public IP as Relay?"

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