On Mon, 9 Apr 2012 21:53:17 +0000, Exchangeskumar wrote: > We used telnet and used a bogus account (not having its existence in the organization) to send emails to valid users within the company . Version of exchange 2003 That's not a description of a SMTP relay, it's the way anonymous SMTP connections work. > Can some one let me know how it can be prevented You mean "how can i prevent spoofing"? You can use SenderID. http://www.microsoft.com/mscorp/safety/technologies/senderid/default.mspx http://www.openspf.net --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

hi, Yes, it is not open relay. You can see this link. Determine whether the Exchange Server is an open SMTP relay:http://support.microsoft.com/kb/324958 So if you want to prevent your issue that you say. You can use the sender ID filter. If your exchange is SP2, you have got the feature already. You can see this link to enable and set the sender ID feature:http://www.msexchange.org/tutorials/configuring-enabling-sender-id-filtering-exchange-2003-sp2.html hope can help you thanks, CastinLu TechNet Community Support

Hi We used telnet and used a bogus account (not having its existence in the organization) to send emails to valid users within the company . Version of exchange 2003 Can some one let me know how it can be prevented What are the business , functional , security , technical , operational requirements of preventing open relay

On Mon, 9 Apr 2012 21:53:17 +0000, Exchangeskumar wrote: > We used telnet and used a bogus account (not having its existence in the organization) to send emails to valid users within the company . Version of exchange 2003 That's not a description of a SMTP relay, it's the way anonymous SMTP connections work. > Can some one let me know how it can be prevented You mean "how can i prevent spoofing"? You can use SenderID. http://www.microsoft.com/mscorp/safety/technologies/senderid/default.mspx http://www.openspf.net --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

hi, Yes, it is not open relay. You can see this link. Determine whether the Exchange Server is an open SMTP relay:http://support.microsoft.com/kb/324958 So if you want to prevent your issue that you say. You can use the sender ID filter. If your exchange is SP2, you have got the feature already. You can see this link to enable and set the sender ID feature:http://www.msexchange.org/tutorials/configuring-enabling-sender-id-filtering-exchange-2003-sp2.html hope can help you thanks, CastinLu TechNet Community Support