I have one client that have external party to set up Exchange 2007 SP1. They have several receive connectors with different sublet and their default receive connector does not have anoymous users checked. Can anyone help what's the reason that they create several receive connectors? Thank you.

Hi, For Applications those want to relay message from different-different subnet to internet you must have seperate receive conenctor. It does not matter you have enabled "Anonymous access" on default receive connector, Because It will work only for intranet email relay but for internet you must have new receive connectors. http://exchangepedia.com/2007/01/exchange-server-2007-how-to-allow-relaying.html Anil

I am reading that link. if the default receive connector has enabled "Anonymous access" , is it open relay? thank you.

I am reading that link. if the default receive connector has enabled "Anonymous access" , is it open relay? thank you. Yes unless you have a mail filtering that is in face of the Exchange server that require anonymous to be enabled.

Do you have still any question now ? Please let us know.Anil

Thank you. Now, If we add another HUB server for this client at different site, I have the default receive connector enabled "Anonymous access" When I use STMP command to test on the second HUB server and I got "unable to relay" So, it is not an open relay?? For the second HUB server, do I need to create all receive connectors that match all receive connectors on the first HUB server? Thank you for your help.

If you have enabled "Anonymous access" on default receive connector then you can send message to internal users, But for external you have to create new receive connector (As I said above URL). For your situation , Yes you have to create new receive connector at new HUB server.Anil

Hi Anil, I am still confused at this and sorry to bother you again. I thought that if I enabled "Anonymous access" on default receive connector, we are able to receive emails from outside. If we need to send emails outside, we need to create the send connector. Thank you for your help.

Hi, Your are correct. We use send connector for deliver email to outside world. But when you want to setup relay from internal source , let say some applications then you need to have receive connector. Thumb Rule "If you talk about relay means you are talking about receive connector" See below URL for all connector diffintion. http://www.theemailadmin.com/2010/01/understanding-exchange-server-connectors/ Is it make sense to you ?? Anil

Hi Anil, Thank you for your follow up and help. But, according to http://msexchangeteam.com/archive/2006/12/28/432013.aspx if I enabled "Anonymous access" on default receive connector, it will not make it open relay automatically. Is this right?

Thats correct, setting anonymous does not make it an open relay. If you need your CAS servers to accept internet mail then you need to set anonymous on the default receive connector as in the article below, however you need to ensure that you don't have externally secured checked on the connector authentication tab, that would make it an open relay. Configuring Exchange 2007 Hub Transport role to receive Internet mail http://msexchangeteam.com/archive/2006/11/17/431555.aspx James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com