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  • multiple domains

    Can exchange 2010 host multiple domains, it so how is it done, and what is needed if each domain is required to have its own public ip address.

    Some Direction would be greatly apprecitated

  • #2
    Re: multiple domains

    yes, a single exchange server can accept email for multiple different domains - you can even have separateemail addresses being only applied to certain OUs

    no, you do not require multiple IP addresses.

    you would need to research "exchange 2010 add additional domain name"
    technet will then help you out
    Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

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    • #3
      Re: multiple domains

      thanks for the reply,

      but each domain requires a ip address to help overcome reverse dns issue, so could exchange handle multiple domains where each domain requires its own ip address

      Comment


      • #4
        Re: multiple domains

        That is incorrect.
        If every domain required its own IP address, there wouldn't be enough IP addresses on the planet. I know of a server in the USA that hosts in excess of 25,000 domains.

        When it comes to reverse DNS, all the remote site is looking at is the server that is sending the email. The actual domain on the email doesn't matter.

        So if I use hotmail.com as an example - the same servers are used for hotmail.com, .co.uk, .de, .fr etc. They all work for email.

        As long as the host name on the Send Connector (host.example.com) matches the reverse DNS record on your IP address, the server can have as many domains as you like.

        Furthermore, even if you did have multiple IP addresses, it isn't possible with Exchange (nor most email server products) to have the email go out through different gateways depending on where the email was sent from - everything is routed based on the destination.

        One IP address, one host name. Use the same host name for everything.
        If you want to hide, then register a generic host name to use for the public facing part, although it is very hard to hide it completely.

        Simon.
        --
        Simon Butler
        Exchange MVP

        Blog: http://blog.sembee.co.uk/
        More Exchange Content: http://exchange.sembee.info/
        Exchange Resources List: http://exbpa.com/
        In the UK? Hire me: http://www.sembee.co.uk/

        Sembee is a registered trademark, used here with permission.

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        • #5
          Re: multiple domains

          thanks

          this is the issue

          I have 7 domains

          4 have their own ip addess and 3 use the same.

          I have the reverse dns setup with my isp

          mail.xyzcompany.com ip address: xxx.xxx.xxx.107
          mail.abccompany.com ip address: XXX.xxx.xxx.108

          can exchange facilitate that mail comong from xyzcompany is coing from xxx.xxx.xxx.107 and mail from abccompany is coming from xxx.xxx.xxx.108

          can exchange do this

          SG

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          • #6
            Re: multiple domains

            Exchange doesn't care about external IP addresses, that is your router's job.
            However if you wish to use TLS (aka SSL over SMTP) then you will one host name, one IP address for all domains to connect to.

            Simon.
            --
            Simon Butler
            Exchange MVP

            Blog: http://blog.sembee.co.uk/
            More Exchange Content: http://exchange.sembee.info/
            Exchange Resources List: http://exbpa.com/
            In the UK? Hire me: http://www.sembee.co.uk/

            Sembee is a registered trademark, used here with permission.

            Comment


            • #7
              Re: multiple domains

              thanks

              so i should have the router handle the ip address

              ie many outside ip address to one internal ip address

              so exchange does not care it only handles mail thru the internal ip address

              "so it does not make a differnece that the outgoing mail with have a different ip address then incomming mail"

              still alittle condused

              Comment


              • #8
                Re: multiple domains

                What is confusing?
                As long as all IP addresses point at Exchange, Exchange will accept the email.
                You don't need multiple IP addresses for Exchange to support multiple domains. A single IP address is all that is required.

                Simon.
                --
                Simon Butler
                Exchange MVP

                Blog: http://blog.sembee.co.uk/
                More Exchange Content: http://exchange.sembee.info/
                Exchange Resources List: http://exbpa.com/
                In the UK? Hire me: http://www.sembee.co.uk/

                Sembee is a registered trademark, used here with permission.

                Comment


                • #9
                  Re: multiple domains

                  Originally posted by sgoldberg View Post
                  "so it does not make a differnece that the outgoing mail with have a different ip address then incomming mail"

                  still alittle condused
                  No. It doesn't matter at all that they have different addresses. A good example:

                  One of my clients uses messagelabs for inbound email. What this means is the MX record for client.com is tower14.messagelabs.com (or whatever)

                  When the client SENDS emails, they send it directly without going via messagelabs, so te message comes FROM server14.client.com

                  Basically, as Simon has pointed out:

                  You can assign multiple domain names to one single IP Address. It doesn't matter what the host REPORTS itself as when sending mail outbound, as long as it resolves.


                  for instance, I can have my mail being received for 15 domains on mail.company.com

                  I can then have mail sending out from an entirely differerent server called outbound.company.com, as long as outbound.company.com resolves to an ip addrss, and the ip addrss resolves to outbound.company.com
                  Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

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                  • #10
                    Re: multiple domains

                    i understand what your are saying as multple domains one ip, the issue is the reverse dns

                    mail.abccompany.com ip address xxx.xxx.xxx.100
                    mail.xyzcompany.com ip address xxx.xxx.xxx.101
                    mail.ghgcompany.com ip address xxx.xxx.xxx.102

                    all go to single router/firewall direct traffic intnallly to xxx.xxx.xxx.10 - mail server

                    all outbound mail goes to mailout.company.com with an ip address xxx.xxx.xxx.125, so my reverse dns would go to mailout.company.com on ip address xxx.xxx.xxx.125

                    so muliple inbounds and a single outbound

                    so the outbound mail will come from one ip address and none of the companies using mailout.company.com will lose their identity, mail will still come from [email protected] , [email protected] and so on...

                    is this the way it works

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                    • #11
                      Re: multiple domains

                      You need to forget about the reverse DNS for inbound email.
                      If you have three domains, with three different MX records on three different IP addresses, then as long as the router can send the traffic to Exchange, they will work.

                      Complete waste of IP addresses mind you, but it will work.

                      For outbound, the email can only come from one IP address. That is where the reverse DNS entry is key. You will need to decide which one it is, set the router and FQDN on the send connector to match.

                      Simon.
                      --
                      Simon Butler
                      Exchange MVP

                      Blog: http://blog.sembee.co.uk/
                      More Exchange Content: http://exchange.sembee.info/
                      Exchange Resources List: http://exbpa.com/
                      In the UK? Hire me: http://www.sembee.co.uk/

                      Sembee is a registered trademark, used here with permission.

                      Comment

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