Exchange 2003 SMTP security lockdown procedures

Im using Small Business Server for exchange 2003 mail management.

Periodocially i find that my server is being used to relay messages by spammers.

Is there a consise checklist of security steps i should follow?


mbalsamAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

SembeeCommented:
Exchange 2003 is relay secure out of the box, so something has been changed.

There are three main ways that an Exchange server can be abused...

- configuration error on the SMTP virtual server or SMTP Connector turns the machine in to an open relay

- authenticated relaying - where the administrator password has been compromised and is being used to allow messages to be sent through the server.

- NDR spam - this is where messages are sent to your server with invalid email addresses on purpose. Your server then tries to bounce them back to the "sender" - who is spoofed and is the real target.

For NDR spam you should deploy recipient filtering and the tarpit.
http://www.amset.info/exchange/filter-unknown.asp

For authenticated user relaying, you need to look at changing the settings.
http://www.amset.info/exchange/smtp-relaysecure.asp

Finally, for checking whether the machine is an open relay, see my article here:
http://www.amset.info/exchange/smtp-openrelay.asp

Simon.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Exchange

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.