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  • Can't receive Email on domain.

    Please reference this post http://forums.petri.com/showthread.php?t=19752 for extra info - This is what I am trying to accomplish but I dont know if it is possible from the way it is looking -
    A client of mine owns a Windows 2003 server with Exchange 2003 SP2 setup - they previously had their website / email hosted with another company - Exchange connectors were setup to communicate to mail.example.org. This exchange server also serves for multiple other functions (DHCP, DNS,FILE, APP, ect) - They decided that they wanted to host their own website / email since the company was poor to updating -
    Nothing has changed on the Exchange server (which is also the DC/GC) for example.local - we setup another server with Windows 2003 server Web edition on it - It has been joined to the Domain - its sole purpose is to host the website/ftp/email (smtp / pop).
    Each server has its own Global IP
    The website / extensions are all in Vertigo
    The FTP / SMTP Virtual server are all in IIS 6 (SMTP virtual server domain name is mail.example.org)
    The Pop3 Service configured - Domain = mail.example.org > mailbox's are setup.
    The web server has DNS setup to for hosting - It manages the NS/WWW/FTP//MAIL - There is a MX record setup for it with an associated HostA record and a reverse zone with a PTR to mail.example.org
    Web/FTP - work like a charm
    Email is a different story - I setup a test email account @ example.org and configured the account in my Oulook2007 (using mail.example.org for both smtp/pop) (along with my personal @ example.com) and I am able to send email from the mail.example.org to the mail.ptech.com - but from ptech.com to mail.example.org nothing happens - it send properly, and I get no failure. But I never receive the email and it never shows up in the pop3 mailbox -
    I have called my ISP and they said my DNS is setup properly - they have configured their PTR records and still with no avail I have been unable to get this to work - they tell me that they dont need a MX record since I have it in my DNS and my DNS responds to queries for the MX record - but for giggles I was able to get them to setup a MX/A Record -

    Now from all this info I have few questions -
    1. Since they just setup this MX should I delete my internal MX/PTR and keep the A record for mail.example.com ? or leave it alone (but wont that display 2 MX records on queries?)?
    2. Once I am able to get emails to my pop3 mailbox's (if I ever do) does anyone see anything wrong with this setup (not warnings just that it WILL NOT work)?
    3. Any suggestions on what could be the problem? Also note that the MX record from the ISP was just setup only 30 mins ago and will obviously take hours before root hints are updated.
    I am working with a little budget and have 95% of it up (I am able to send from OWA via exchange from orginal server outbound to myself @ ptech.com) so hopefully I can figure out what is stopping these emails from getting to my server.

    Also one quick note, If I look at the internet headers from my email (from [email protected] to [email protected]) it shows the email coming from the Exchange server IP (even though the connector points to mail.example.org)
    So to test I took the Exchange server offline and I was still able to send mail - for whatever reason it still shows the exchange server address (probably internet routing hasn't been fully updated yet was my thought since this webserver / NS / DNS has only been up live for 3 - 4 days now.

    Thank you for your time.
    J

  • #2
    Re: Can't receive Email on domain.

    Hi there, I will try to answer some of your questions with regard to your problem.

    The first issue is with your DNS records. My understanding is that you configure your A record, MX record and Aliases with the domain registrar that is responsible for that domain. Normally the ISP only gets involved when you are having problems sending mail to organisations that will not accept mail that comes from an IP address that cannot be resolved back to a domain name. Hotmail and Yahoo are typical examples of this. I think that is what you have done. It wouldn't be normal for the ISP to create and be responsible for your MX records unless they are the organisation that you purchased the domain from.

    The second issue is with regard to your internal records, It is not a bad thing to create records internally in your DNS zone for that domain as it helps local requests to resolve domain names such as the web site, FTP site and anything else that may be hosted on the server. This stops local hosts having to be forwarded externally for DNS requests.

    Thirdly you haven't mentioned how the server connects to the internet. If it is just a modem connection, then it could just be a firewall issue. If it is a broadband router then port forwarding requires to be set up. This means that any smtp, pop3 request be sent to a particular machine, such as the server. Therefore you would allocate any port requests such as port 80, 25, 110 to forwarded to the machine IP address that hosts these services. If it isn't set up, then mail can be sent out but replys will not come back, as when they reach the firewall or router, it will simply drop the packets as the port in question may be blocked and it doesn't know what to with it anyway. There is a default time scale where the mail server sending will eventually give up, 48 hours and then you will start getting NDR's. You will not get anything immediately unless the destination is deemed unreachable.

    This post doesn't answer all your questions however hopefully it is of some use.

    Regards,

    Jewen.

    Comment


    • #3
      Re: Can't receive Email on domain.

      Jewen,
      Thank you for your reply - So I shouldnt have had them setup an MX record for mail.example.org? (Since they are not hosting my domain *I am* only providing me the IP)

      I had all the records setup here (the only records not on here now are the mx/a for mail) - I could send email I just could not receive email back.

      Network connectivity
      ISP (cable)->Cable Router>Netvanta 1224r router (with multiple VLAN's)>SMC Switch> VLAN50 is the Servers VLAN with 1:1 forwarding on all ports (for the time being) for Global IP to Internal IP of the server.

      Everything else works great - The website pulls up, FTP works, I can send email, just can't receive.

      Comment


      • #4
        Re: Can't receive Email on domain.

        I think that you misunderstand the process of domain name records. You might be hosting the services e.g web hosting , email etc but unless you are a domain name registrar which I don't believe you are, it is the registrars name servers that publish your external DNS records to the wider world. Therefore your MX records must be configured with the domain name registrar that the domain has been purchased from.

        You can create records internally in your DNS zone for particular such as a A record, MX record and Aliases for ftp, www, smtp, pop3, but they only work internally, and are used apart from the A record to resolve the locally hosted services rather than being forwarded to an external DNS nameserver. When you say that the web works and ftp works, are you testing from inside the network? They will work if that is the case because you have configured the relevent settings within the DNS zone internally, therefore these sites and services are being resolved locally. Does it work from another external network. If these settings are not being published externally you will find that you will not be able resolve ftp.yourdomain.com to the IP address that you are using from home etc.

        I suspect that the reason you cannot recieve mail is that there is no external MX record to tell the other mail servers where to send it to.

        Finally your ISP is responsible for allocating you either a static or dynamic IP address and again as I said in my previous post that unless that is whom you registered the domain name with, or host your email they have no real part to play in your DNS records. An exception to that is a SPF record to stop email from your domain name being blacklisted or at least blocked.

        Hopefully this may clarify your problem.

        Regards,

        Jewen.

        Comment


        • #5
          Re: Can't receive Email on domain.

          Wow, this thread has gotten complicated. Just to clarify:

          The company that registered your domain name is NOT neccessarily the company that hosts your DNS records. Anyone can host your DNS records, while at the same time someone else registered your domain name, while at the same time someone else hosts your web site, while at the same time someone else hosts your email, etc., etc. None of the previous are mutually exclusive.

          In order for external email to go to your internal email server you need:

          1. Create the appropriate NAT and Traffic rule on your firewall or router to allow SMTP traffic to flow in to your email server.

          2. To find out who hosts your DNS records. Do an nslookup or whois lookup to find out who it is.

          3. Have the party identified above create an A record for the public ip address of your email server.

          4. Have the same party create an MX record that points to the A record created above.

          5. Delete the internal DNS records that refer to any services you are exposing from your external DNS, such as MX, CNAME, A records for ftp, www, etc. These are unneccessary for your internal clients.

          6. Configure your Exchange server to receive email for the external domain name with the appropriate Recipient Policy, etc.

          7. Configure your email clients to connect to your Exchange server.

          8. Go home and sleep easy since your email is now working perfectly.

          Comment


          • #6
            Re: Can't receive Email on domain.

            I appreciate your clarification. You are correct that the registrar that you have purchased the domain name from doesn't necessarily have to host the DNS records. I personally didn't want to complicate DNS records more than I had to. I felt it is easier to explain the process of DNS records being setup by just using the current registrars nameservers.

            When you say internal DNS records are unecessary I would disagree, some router dislike the process of requesting a web site that requires external resolution only to find that it is hosted internally on the same network. I think it is a loopback type scenario. Generally in this situation you find the page that is eventually displayed is the login page to your router configuration console. Therefore an internal DNS records stops this from happening. This can also be resolved by adding an entry manually into the host file on every machine on the internal network.

            Regards,

            Jewen

            Comment


            • #7
              Re: Can't receive Email on domain.

              Found out from the other thread that PORT 25 is not configured to permit traffic into the Exchange server.

              We should await the results of Joeqwerty's suggestion number 1 before being able to go any further on this one.
              Best wishes,
              PaulH.
              MCP:Server 2003; MCITP:Server 2008; MCTS: SBS2008

              Comment


              • #8
                Re: Can't receive Email on domain.

                Port 25 is working properly -
                It is not going to the Exchange server - the exchange server looks @ the webserver for pop3/smtp email and grabs and stores it for local users to access via OWA
                Testing email again. Same issue resides.

                Comment


                • #9
                  Re: Can't receive Email on domain.

                  JQ
                  1. Yes 80 / 110 / 25 are all getting to the server
                  2. We host the dns records
                  3. In DNS there is a HOSTA record in the Forward Zone (example.org) of the Global IP
                  4. Have created MX along with MX records that point to godaddy - along with have a HOSTA record of mail.example.org assocaited to the Global IP
                  5. They are not there. Only External records.
                  6. Exchange configured to look @ mail.example.org (pop/smtp connectors)
                  7. Been long done and working (when website/email was previously hosted externally)
                  8. still not resting easy

                  Comment


                  • #10
                    Re: Can't receive Email on domain.

                    Maybe I am missing something, but how are you hosting your own DNS records?
                    Are you running a Public DNS server? If not all the DNS records should be configured for that domain at your registrar GoDaddy.

                    You haven't mentioned if you are able to able to access the web site and ftp site from an external network. It still doesn't sound to me that you have configured your DNS record in the correct place. Pointing an internal DNS MX record at GoDaddy is not going to work. You create an A record that points to the public IP address that you have, then you create a MX record points to the A record. This is all done at GoDaddy's end.

                    Regards,

                    Jewen

                    Comment


                    • #11
                      Re: Can't receive Email on domain.

                      I have been able to access the website / FTP / send email from day one (unless i made major changes to dns) from external networks.
                      Also in Post 1. I stated WEB/FTP work fine. I meant externally -
                      I have no DNS management @ godaddy - and yes I agree that it wont work pointing mx records @ them since the mail server I am going for mail.example.org (example.org being registered to godaddy but nothing is being hosted by them.

                      Comment


                      • #12
                        Re: Can't receive Email on domain.

                        I have just checked by using nslookup ... type=mx that your MX record points to an IP address which, when I telnet that on port 25, your Exchange server answers and I can say "HELO" to your domain name.

                        So right now, I reckon all DNS stuff and so on is pointing to the right place. Can you have an external friend send a test email and see if it arrives in Exchange?

                        I think the main change made was that the router used to answer on port 25, but now Exchange answers. So, fingers crossed, it should work.
                        Best wishes,
                        PaulH.
                        MCP:Server 2003; MCITP:Server 2008; MCTS: SBS2008

                        Comment


                        • #13
                          Re: Can't receive Email on domain.

                          Edit
                          Ok I see that you do host your own Public DNS, I think you have already been told that its not a great idea.

                          However doing a nslookup, I think the value of your MX record being set to 0 might be a problem. Change the value to 10 and see if that helps.



                          Correct me if I am wrong but a registrar needs to have a record of the domain name in the shape of a A record, MX record ,CName, Alias etc all pointing back to the public IP address regardless of whether it hosts any service or not. Otherwise the external world will not be able to resolve mail.example.com.

                          The exception to this is where you host Public DNS namesevers on your network, and of which, you are expected to have at least two of, and will allow you to host your records and resolve queeries from other nameservers on the internet.

                          If the domain is registered at GoDaddy there is an interface which allows you to enter the DNS records of your domain and point them to the public IP address.

                          At the moment I am fascinated to hear how the domain is currently resolved if no nameservers have this information. If on the other hand it is setup with internal DNS on a internal server, which I think it is, I am amazed that it works, especially the web site and ftp.

                          Could you give me the web address so that I can visit.

                          Regards,

                          Jewen.
                          Last edited by jewen; 21st November 2007, 20:03. Reason: Shadowed thread on the same subject

                          Comment


                          • #14
                            Re: Can't receive Email on domain.

                            value is not changed to 10
                            Thanks for catching that.

                            Comment


                            • #15
                              Re: Can't receive Email on domain.

                              I know I mentioned your MX value but that was for your domain and not your clients. Were both MX records set for 0 or just that one?

                              Regards,

                              Jewen.

                              Comment

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