I have a query in relation to Windows SBS 2003 Exchange server.
I've configured the server so that it does not provide any open relay, and tested it using DNSREPORT.COM.
I've noticed that if I do a test via an external Telnet if I use a valid internal address it allows sending of information to another internal address ie. The System was all configured use CEICW wizard.
250 mail.xxxxxx.com Hello [22.214.171.124]
250 2.1.0 firstname.lastname@example.org....Sender OK
250 2.1.5 email@example.com
354 Start mail input; end with <CRLF>.<CRLF>
.250 2.6.0 <DCS001Dq5sLdVxs00000058@mail.xxxxxx.com> Queued mail for delivery
I've changed the name from the above the log from SMTP remains the same largely.
Obviously this could be used by spammers to send mail in. How do I remove this? At least no external person use the mail server for mail relaying expernally.