Hello, I do not know if you will understand me, however I want to ask how it is possible that if a domain has mail server of mail.aaa.com and another domain of mail.bbb.com pointed to it, how is it possible that another domain lets say @ddd.com is received by the same mail server and accepted. I am asking this because the majority of users have @aaa.com or @bbb.com e-mail address however there are others which have additional smtp e-mails set as @ddd.com and @eee.com for example. I want to understand how this domains/e-mails are being directed to this server, is there some kind of MX record on this last 2 domains which are pointing to the mail server mentioned on top. Tanks

On Thu, 14 Oct 2010 21:14:32 +0000, acmsoft wrote: >I do not know if you will understand me, however I want to ask how it is possible that if a domain has mail server of mail.aaa.com and another domain of mail.bbb.com pointed to it, how is it possible that another domain lets say @ddd.com is received by the same mail server and accepted. That would require the ddd.com domain to be in the accepted domains list, and the SMTP address in the ddd.com domain to be assigned to the mailbox. >I am asking this because the majority of users have @aaa.com or @bbb.com e-mail address however there are others which have additional smtp e-mails set as @ddd.com and @eee.com for example. Well, if ddd.com and eee.com are in the Accepted Domains list why would they NOT be accepted and delivered? >I want to understand how this domains/e-mails are being directed to this server, is there some kind of MX record on this last 2 domains which are pointing to the mail server mentioned on top. MX records are just a way for a SMTP client to find the correct server to contact based on the domain of the intended recipient. It isn't necessary that there even be a MX record for mail to be delivered to a particular server. It's quite possible that the sender has knowledge of the server's IP address. If the message is sent by a MAPI/RPC client (including OWA), the SMTP address in the "To:", "Cc:", and "Bcc:" headers are searched for in the AD. If they're found the legacyExchangeDN property value is used to deliver the message. It's also important to remember that the address you see in the "To:" and "Cc:" headers may have no relation to the RCPT TO addresses used to deliver the message. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

So for example from my domain @aaa.com I can send e-mails to @ddd.com to a server that is only authoritative for @hhh.com as long as I know the mail server ip address of mail.hhh.comand this hhh mail server has the ddd mail server as accepted domain. Sorry for the confusion but is this right ? If correct where do I tell exchange to send ddd e-mails to the ip address of hhh mail server. So a mailserver can receive any e-mails which are part of the accepted domain list and delivers them to the user mailbox even if they have nothing to do with their domain name. ( this is what really could not understand how and why ) My thoughts were that emails are delivered based on dns resolution and mail.domain.com MX records. But why is this, would it not be much more clean to have mail.ddd.com with its own mailserver then having mail server hhh accepting e-mails for domain ddd which sounds a bit confusing. Thank your for your time and info

Your accepted Domain list will require MX record on the internet to receive mails . Else how would the sending server know that your public ip is publishing mails for this domain. But if they have additional SMTP address ( secondary ) they would be accepted on primary . a sort Address - rewrite feature in Exchange

On Fri, 15 Oct 2010 05:29:31 +0000, acmsoft wrote: >So for example from my domain @aaa.com I can send e-mails to @ddd.com to a server that is only authoritative for @hhh.com as long as I know the mail server ip address of mail.hhh.comand Let's assume that we're talking about two different e-mail systems (AAA and HHH), both of which are operating at different locations, and neither of them has any knowledge of the other. There are no special permissions, no white lists, etc. Both systems run Exchange 2007 (or 2010). In the AAA system the "Accepted Domains" list includes ony "aaa.com". In the HHH system the "Accepted Domains" list includes ony "hhh.com". With these criteria, the HHH system should refuse to accept e-mail addressed to any mailbox in the domain "ddd.com". In fact, it should reject any e-mail addressed to any mailbox in ALL domains except "hhh.com". You can TRY sending e-mail addressed to a mailbox in the domain "ddd.com" to the HHH system, but it should be refused. HOW you get the mail from the AAA system to the HHH system would require the use of a smart host that directs the connection to the HHH system for all mail sent to the domain "ddd.com". WHY you'd want to do this is another question. >this hhh mail server has the ddd mail server as accepted domain. Sorry for the confusion but is this right ? Well, if the HHH system includes "ddd.com" in its "Accepted Domains" list then: 1) It should accept the e-mail sent to deliverable addresses in the domain ddd.com. 2 )There should be a MX record for the "ddd.com" domain that directs the sending client to the HHH system. >If correct where do I tell exchange to send ddd e-mails to the ip address of hhh mail server. Which of these conditions is true? 1) HHH has "ddd.com" in its "Accepted Domains" list 2) There's a MX record for the "ddd.com" domain 3) The MX record points to a server in the HHH system 4) You have a Send Connector that has "ddd.com" in its address space 5) The Send Connector delivers mail to a smart host in the HHH system If 1, 2, and 3 are true you don't have to do a thing. If 4 and 5 are true than 1 also has to be true. If only 1 is true then you need to make 4 and 5 true. >So a mailserver can receive any e-mails which are part of the accepted domain list and delivers them to the user mailbox even if they have nothing to do with their domain name. ( this is what really could not understand how and why ) Let's be sure that we're talking about DNS domains and not Active Directory Domains. The two don't have to be the same. If your question is "can an Exchange server accept e-mail for domains in the 'Accepted Domains' list even if those domains are different to the Active Directory domain name?" then the answer is yes. If you question is "can an Exchange server accept e-mail for domains that are not in the 'Accepted Domains' list?" the answer is a qualified "yes". In order for it to do that the Exchange server would have to allow the sending sestem to use it as a SMTP relay -- but that's not part of the conditions in the 1st two paragraphs of this reply. >My thoughts were that emails are delivered based on dns resolution That's mostly true, but it's not a hard and fast requirement. The use of SMTP smart hosts make it possible to send e-mail to a machine that has no representation at all in DNS (assuming you know its IP address). >and mail.domain.com MX records. This is the way "normal" e-mail is routed from sending system to receiving system. >But why is this, would it not be much more clean to have mail.ddd.com with its own mailserver then having mail server hhh accepting e-mails for domain ddd which sounds a bit confusing. In that case, I'd need more than twenty servers to handle e-mail where I use only a few (and not because of the number of domains). :-) There's no limitation (well, there is, but it's a pretty big number) on how many domains can be handled a single Exchange organization. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

On Fri, 15 Oct 2010 15:00:49 +0000, Khoj Sahiwala wrote: >Your accepted Domain list will require MX record on the internet to receive mails . Else how would the sending server know that your public ip is publishing mails for this domain. You tell them and they use the IP address to direct mai to your system. I agree that that isn't the "normal" way e-mail is routed, but it's common enough. :-) --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Thanks ...

One of the best well explained answer I have ever been given. Thanks Rich Matheisen