Solved How to configure 2003 server POP3 Service?

November 2, 2011 at 22:20:12
Specs: Windows Server 2003 Standard, Intel Dual Core/4GB
I have installed the server role mail server (POP3 Service) on my 2003 server that has also AD, DNS, DHCP installed. I have supposed what it does is retrieving and storing emails from other mail servers like an email client would do. Then another email client can retrieve emails from the mailbox of this service. So I suppose the mail client would be configured to retrieve emails from this 2003 server and send out email through the same 2003 server.

However I don't see where on 2003 to configure the details of the incoming server and outgoing server for it to work. Searching on the Internet, it only talks about configuring email clients. Can I get enlightened on this matter?


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✔ Best Answer
November 4, 2011 at 03:26:26
To answer your simplest question first, the matter of testing. The mail from: command tells the server the address the mail is coming from. You can use any address here; I'd use a valid email address that you already have (e.g. a Hotmail address). The rcpt to: is who the mail is addressed to. This has to be a valid user on your server. Try Administrator@testdomain.local or, if that fails, Administrator at <insert your server name here>.testdomain.local. As for CRLF, that's just the enter key. That should allow you to test the basic operation of the server.

Domains are a bit confusing. As you say, you have set your server up with a local domain (testdomain.local), but you want to receive mail addressed to your external domain (testdomain.com). You need to tell the SMTP server that it should handle mail for this domain as well as your local domain. Open up IIS Manager and in the "Domains" window of "SMTP Virtual Server" right click and select "New Domain" You want a local (Alias) domain which you name testdomain.com. The server now know to accept mail for that domain.

(Actually, on 2003 that last paragraph may be wrong. I've been testing this on 2008, which doesn't support POP3 any longer - Microsoft wants everyone to use Exchange, as I don't have a 2003 server. From what I read in another link, when you create a domain in the POP3 server it creates that domain in the SMTP one also. So if you've created the domain "testdomain.com" in POP3 configuration you may be OK.)

Your setup should now be configured to accept mail for "testdomain.com" and deliver it to clients. Although the clients belong to a different domain than that the mail is addressed to, it doesn't matter. You just set up the mail account in the client for "testdomain.com". This is exactly the same as setting up another account for, say, "hotmail.com". If you want hotmail and testdomain.com mail you set up accounts for each in your mail client.

But the outside world still needs to be told which server handles mail for "testdomain.com". This is where the MX record comes in. This record in the DNS server hosting information for your domain tells other mail servers where to deliver mail. You'll need an "A" record (just a normal record) pointing to your router (you can call it anything - e.g. "mail.testdomain.com") and an MX record pointing to this "A" record. Then you configure port forwarding on the router to send connections on port 25 to your internal server. The outside world thinks your router is the mail server, but the router know better and delegates that to the real server.

Note that the SMTP server only deals with mail for your own domains; you can't set it up to accept mail for <youraddress>@hotmail.com, for example. If you want such mail to be delivered to your server you'd have to configure mail forwarding in that account. But it's easier just to set up a separate account in your mail client.

Sorry that I can't be really helpful about the POP3 server, but I'm unable to test that setup under Windows. I hope the above makes some sort of sense. Once you "get it" it's all fairly simple, but it can be a bit confusing at first.



#1
November 3, 2011 at 00:12:57
You need to install and configure the SMTP service as well. It is SMTP that sends and receives mail from remote mail servers. Read this article: http://www.techrepublic.com/article...

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#2
November 3, 2011 at 01:37:55
Your hyperlink to an article does not bring up any article at all.

Anyway the SMTP service has already been installed automatically together with the POP3 service.

Where do we put in the mail server URL and port numbers and so on then?


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#3
November 3, 2011 at 02:35:08
Sorry, I put the wrong link there; I've now corrected it. As you have already installed SMTP, I'm not quite sure what you are asking now. As long as you have an MX record pointing to your SMTP server other mail servers will just find it. Outgoing mail can either be directed to a relay server or sent directly to other mail servers (preferred); this is configured in the SMTP settings. Don't worry about port numbers; you don't want to change the defaults.

The SMTP mail server receives mail from the outside world and stores it somewhere. The POP3 server then makes that mail available to clients. You just point the mail clients to your POP3 server using the standard POP3 port.

Here - http://technet.microsoft.com/en-us/... - is a link describing configuration of the SMTP server. (I really have got the right link this time!)


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#4
November 3, 2011 at 04:47:30
Thanks! I suppose the article is referring to server 2008, not 2003, though the principles are still the same.

I have misunderstood that this service would go to other mail servers and pick up the mail. Since we have to change the MX record of other mail servers, that means this server would just play a waiting game, be passive and wait for the delivery.

I suppose the sending out of emails would not go through this service, would it?


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#5
November 3, 2011 at 05:08:14
It's not that the server picks up mail from other servers; it's the other way round. The MX record is on whichever DNS server handles your addresses as seen by the outside world (probably your domain provider). When a remote server sees mail addressed to your domain it goes to that DNS server and looks for an MX record to tell it which server to deliver mail to. They deliver mail directly to your SMTP server.

Pop3 is the other way round. The clients do pull mail from the server. That's why you need both servers - one to listen for request from remote servers who want to send mail to you, the other to listen for requests from clients who want to receive that mail.

You can use the SMTP server to send outgoing mails (you just configure your clients to send mail to your SMTP server); this is more efficient than each client connecting to a remote SMTP server. The only potential problem is whether your ISP allows you to send to port 25 on any server. If so you configure the SMTP server to deliver mail directly to other servers; otherwise you may need to configure it to deliver all mail to your ISP's SMTP server, which would then forward it to the final address.

It might be worth reading the Wikipedia article on SMTP to get an understanding of how these things function. (It's not specific to Windows, but gives a good overview.)


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#6
November 3, 2011 at 23:33:15
I thank you ijack for your patience perseverance.

Things that I am not too sure are as follows. I set up the 2003 server with a local domain as Windows installation suggested, such as "testdomain.local". I also have free dynamic domain set up for the external IP address, i.e. the address to the ISP router, such as testdomain.com. The server has AD, DNS and DHCP installed. I would like to set it up as a full-fledged server eventually, mainly for testing and exercise.

The first function I would like to be able to have is sending and receiving mail through the server. The mail server (POP3 service) has been installed successfully according to the installation process. I intend to set up the router firewall forwarding port 25 and port 110 to this particular 2003 server, hence the mail server inside the firewall. Though I have multiple email accounts which do not all use the same default ports. I just pick those that use the default for exercise. So I suppose I shall be using the dynamic IP address and the free domain testdomain.com for the MX record. I understand the IP address from the ISP does not change that often. Certainly I need to keep a close eye when I am testing.

When I try to follow http://support.microsoft.com/kb/323350 to test the SMTP service, Some steps do not end up exactly the same. I am not too sure if I should enter exactly "mail from:email@domain.com" and then "rcpt to:youremail@yourdomain.com". I do not remember how to enter "CRLF".

What does it mean by associating user with the mailbox? What if they are not associated?
If I set up a few mailboxes, when the email messages come in, which mailbox they would go?

When the clients pick up or send email messages, I suppose the mail client should be set up using the public domain testdomain.com, not testdomain.local even though the client's computer and the server are sharing the same local network. Am I right? The server and the mail server should have the same domain name, shouldn't they? Do you think clients both belong and not belong to the domain would be able to send and receive mail through the same server, or mail server for that matter?


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#7
November 4, 2011 at 03:26:26
✔ Best Answer
To answer your simplest question first, the matter of testing. The mail from: command tells the server the address the mail is coming from. You can use any address here; I'd use a valid email address that you already have (e.g. a Hotmail address). The rcpt to: is who the mail is addressed to. This has to be a valid user on your server. Try Administrator@testdomain.local or, if that fails, Administrator at <insert your server name here>.testdomain.local. As for CRLF, that's just the enter key. That should allow you to test the basic operation of the server.

Domains are a bit confusing. As you say, you have set your server up with a local domain (testdomain.local), but you want to receive mail addressed to your external domain (testdomain.com). You need to tell the SMTP server that it should handle mail for this domain as well as your local domain. Open up IIS Manager and in the "Domains" window of "SMTP Virtual Server" right click and select "New Domain" You want a local (Alias) domain which you name testdomain.com. The server now know to accept mail for that domain.

(Actually, on 2003 that last paragraph may be wrong. I've been testing this on 2008, which doesn't support POP3 any longer - Microsoft wants everyone to use Exchange, as I don't have a 2003 server. From what I read in another link, when you create a domain in the POP3 server it creates that domain in the SMTP one also. So if you've created the domain "testdomain.com" in POP3 configuration you may be OK.)

Your setup should now be configured to accept mail for "testdomain.com" and deliver it to clients. Although the clients belong to a different domain than that the mail is addressed to, it doesn't matter. You just set up the mail account in the client for "testdomain.com". This is exactly the same as setting up another account for, say, "hotmail.com". If you want hotmail and testdomain.com mail you set up accounts for each in your mail client.

But the outside world still needs to be told which server handles mail for "testdomain.com". This is where the MX record comes in. This record in the DNS server hosting information for your domain tells other mail servers where to deliver mail. You'll need an "A" record (just a normal record) pointing to your router (you can call it anything - e.g. "mail.testdomain.com") and an MX record pointing to this "A" record. Then you configure port forwarding on the router to send connections on port 25 to your internal server. The outside world thinks your router is the mail server, but the router know better and delegates that to the real server.

Note that the SMTP server only deals with mail for your own domains; you can't set it up to accept mail for <youraddress>@hotmail.com, for example. If you want such mail to be delivered to your server you'd have to configure mail forwarding in that account. But it's easier just to set up a separate account in your mail client.

Sorry that I can't be really helpful about the POP3 server, but I'm unable to test that setup under Windows. I hope the above makes some sort of sense. Once you "get it" it's all fairly simple, but it can be a bit confusing at first.


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#8
November 4, 2011 at 23:04:22
I have done the test again and it seemed to work. Email messages were set to send from some valid outside email address to any name in the test domain, even the name does not exist on the server.

Initially I set up the server with the public free domain. However one of my friends advised not to due to security issues. I am not too sure if it makes any difference. With the public domain they still can access without the need of knowing the local internal domain anyway.

Are you saying one of the domain names under the Default SMTP Virtual Server need to be the one for the emails coming in or the free external domain of the router? I have three entries there as follows. The third or the last one is the domain name for which the email messages would be coming in. If I add more domains, does it mean email messages of more domains can come in?
-svr2003.testdomain.local Local(Default)
-e4198031-1915-4381-a2a1-87fe8a1ea04a._msdcs.testdomain.local Local(Normal)
-maildomain.com Local(Custom)

Which mailbox will the email messages go to?

Why do we only need to forward port 25 which is for outgoing message?? What about 110 for incoming messages?

On the POP3 Service Properties there is an option of "Always create an associated user for new mailboxes", What does this mean?


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#9
November 5, 2011 at 00:37:48
The domain names for the virtual SMTP server are those that it will accept mail for. You can put any that you like here, but to be of any use external DNS servers must point those domains to your router. SMTP does not pull mail from other servers. So to get mail from Hotmail your clients need to retrieve it from the hotmail POP3 server (for example). The SMTP server saves messages in files on your server. The path name for this is specified in the properties for the default server.

You don't need to forward port 110 unless you have clients accessing your POP3 server from the Internet. On your internal network port 110 is used for clients to pull mail from your server. So nothing sends from the outside world to port 110 through the router (unless you need access to your POP3 server from the Internet). External mail servers use port 25 to talk to your SMTP server, which is why it needs to be forwarded by the router.


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#10
November 5, 2011 at 03:43:43
When we add mailbox to the domain, are we supposed to add mailbox with the same user name of those email messages coming to the server? And that's where the messages go. They go to their respective mailboxes that have the same names and same domains, don't they?

Under what circumstances, we would create a mailbox without associated user?


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#11
November 9, 2011 at 19:00:09
For some reason I can't vote one of the response back up after I accidentally voted it down.

If possible, please answer my last questions for this subject below.

When we add mailbox to the domain, are we supposed to add mailbox with the same user name of those email messages coming to the server? And that's where the messages go. They go to their respective mailboxes that have the same names and same domains, don't they?

Under what circumstances, we would create a mailbox without associated user?

Thanks a lot!


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#12
November 9, 2011 at 23:25:52
According to this article http://www.windowsnetworking.com/ar... you create the mail domains and accounts in the POP 3 server configuration. By a "mailbox without a user", do you mean some default account that unrecognized mail will go to? Some mail servers let you configure tis, but I'm honestly not sure how to do it in this case. Such mailboxes do tend to end up with a lot of Spam.

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#13
November 9, 2011 at 23:47:31
Thanks for your patience anyway.

I mentioned mailbox without a user, just because the setup referred to mailbox with associated user. So I simply presumed there must have been an opposite situation.


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