How to stop Relaying SPAM.

[abrannon]

We have a Exchange 2000 server that is constantly relaying spam.

It is not an "Open Relay Server". But it is forwarding spam from other servers.

I can not turn off Relaying because I have POP3 Clients around the world. I have it set to only realy from Authenticated users, but this allows any SMTP Server to relay through my server.

My plan is to allow relaying from only one subnet. I can require all of my users outside of my domain to use a VPN to access there mail. By doing this I can insure that they all are in the same Subnet.

Will this work, if not why?

Also is there a better way to stop this from happening?

 

[zxmax777777]

i had a similar problem (using Merak Mail server) , and i found out that for some reasong, the relaying spam server knew the user name and password of one of the accounts, specially if you don't have a good user name and passsword complexity.
just a thought

 

[minxca]

http://www.vamsoft.com/orf/authattack.asp

 

[mtavana]

The Queues (Outbound Messages Awaiting Delivery) get full with returned (undeliverd) spam mail that has no originator only (<>). Is there any way to stop or ID the originator so it can be blocked by address or IP refusal. Thanks Moe

 

[Marcs41]

See the FAQs HERE about relay !

Marc
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