How to block Anonimous Access to E-mail Server

[soportesinaki]

Dear Sirs,

We have recently installed an Exchange 2003 server as e-mail server and we have migrated the e-mail services to our enterprise this weekend. I thought that if I wanted to block anonymous users to use the smtp I had to un-check the anonymous access in the authentication window of the virtual smtp server.

I did so, but only authenticated users could send e-mail to the different accounts. It was impossible to receive external mail this way. I had to check again the anonymous access option.

How could I block the anonymous access without having problems with the incoming mail? I would like to block it, to prevent spammers using our server.

Thank you for your help!!
Best regards,

Iñaki

 

[beefstew]

By defalut Exchange server does not relay, it is locked down. It does however allow anonymous access to the server so that mail can be delivered to local Mailboxes from anyone, including from the internet. if you turn off anonymous access then only users who have authenticated can send mail to the SMTP virtual server.

 

[soportesinaki]

Yes, but if I do so I have problems receiving external mail. Only authenticated users are allowed to send us e-mails.

 

[nsantin]

When you say "Only authenticated users are allowed to send us e-mails", do you mean Exchange authenticated users within the same organization?

If you want to receive any mail from anyone in the internet outside of your exchange routing group then you need to allow anonymous access.

To combat spam turn on IMF or get a spam utility.

 

[beefstew]

Of course,

What you generally do in this situation is setup a Mail relay server, usually in a DMZ and have this block spam e-mail. There are loads of different products out there to use. Spam Assasin is a good one. The Mailbox server can then be left with the default settings, only relaying for autheticated users, but everyone can access the to it to deliver mail locally.