Stopping Open Relay in IIS 6.0 -- iis smtp nntp

joatman71
10/19/2006 9:50:13 AM

I am using IIS 6.0 on a Windows 2003 Server for incoming and outgoing
email. I need to accept anonymous incoming email destined for the
server and allow all outgoing email originating from that server. When
I have SMTP turned on I immediately start getting hundreds of relay
messages, some of which are relayed.

I allow anonymous authentication, and in the relay restrictions section
I am granting relay rights to only a few private (internal) IP
networks. I am also allowing all computers which successfully
authenticate to relay. I turned this off and had the same problem
though.

Everything looks right to me, but I still see relay messages going out,
not to mention thousands of messages that get put into the bad mail
directory.

Are there known bugs or message formats that get around relay
restrictions? Am I not set up correctly?

Dr. Network
10/20/2006 10:32:08 AM

Try setting the relay filter to just relay 127.0.0.1.

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KL
10/22/2006 7:06:12 PM

You should not allow any computer that authenticates to relay, and you
should look into what ip's you allow, don't allow complete subnets.

It's also possible you have an issue with ndr attacks, where the spammer
sends to invalid emails on your server and then the ndr is sent out to
whatever the reply-to in the spammers email was set to, download this script
to make that stop:
http://www.lundin.info/filterrecipients.aspx

KL.

"joatman71" <brassfoley@gmail.com> skrev i meddelandet
news:1161276613.063714.140500@i42g2000cwa.googlegroups.com...
[quoted text, click to view]

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iis smtp nntp : Stopping Open Relay in IIS 6.0