General discussion


New Exchange Installation

By gduncan ·

I am to install Exchange Server 5.5 and need some advice as to the precedure for changing from a POP3 based system (ISP hosted)to SMTP.

We have a NT network and connect to our ISP via a ISP configured router through a 256k leased line.

My first concern is our internal IP range, we have a private (non-legal) internal scheme, Our PDC (NT) has a static address of, it lists the default gateway as (router installed by ISP) it runs DHCP and hands out addresses in the range - our client computers access the internet simply by addressing the PDC through the LAN (no proxy/no scripts) which then I assume addresses the gateway and passes the request out through the router, through our leased line to our ISP's DNS server's.

We have a BDC and it is my intention to set-up what will become our Exchange server as a Member server with the address


Now this is where it gets a bit tricky, it seems to me that in order to configure the Exchange server for outbound mail all I need to do is to set-up the Internet Mail Service to forward all messages to host (ISP DNS server) which should not be a problem as long as I set-up the default gateway on the member server to point to the router (


Now this is where it gets very tricky, at some stage we are going to have to switch from POP3 to SMTP and this is where my knowledge breaks down a bit - I believe that with POP3 we reach out and negotiate the retrieval of mail and that with SMTP the ISP directs it to a address - my big question is "will the ISP be able to direct the SMTP stream to our member server, internal address ?"

Does any of this make sense, am I on the right track, will it all go horribly wrong on D-Day ???


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Still some questions

by curtfeece In reply to New Exchange Installation

What type of router do you have? Is the ISP providing firewall capability in the router? It sounds as though they are already doing Network Address Translation (NAT) for you. Typically, I would suggest a publicly registered range of IP addresses for you and then you provide your own firewall (maybe MS ISA Server). If that is the case, ISA will allow you to do your own NAT and SMTP behind the firewall is a snap. Sounds like you still need to talk to your ISP and find out what is going on with them.

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More Questions

by JordanA In reply to New Exchange Installation

Do you have a registered Domain Name? I found a neat little program that you can install on your Exchange server that will download your pop mail from the ISP into your Information Store.


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New Exchange server

by jtakiwi In reply to New Exchange Installation

To preface my reply, I have done this sort of work for a few clients in the past. Basically you have two directions to go.

First if you recieve company mail through the ISP's address (ex. or you just have to register a domain name, get one public ip address, get the MX (mail) record registered, get a router (or ISA server, which works pretty well) to do the NAT (address translation from public to private). Then, have your isp, or your users forward their mail to the newly installed Exchange server ou set up. W/ Outlook 2000/XP you can have your users check their smtp and pop3 mail w/ the same client. When you set up the Exchange server, it will use DNS to send mail by default, just make sure yourDNS entries in the tcp/ip properties are correct onthe exch server.

Or, if your isp hosts your mail as, get a public address and have them change the mx record to the new address (assumes that the ISP registered the domain name for you). Then, set up you router / firewall to do the Network Address Translation from the Public address to your private addressing.

If you have any other questions, I'm sure I left a couple of things out (they always pop up during the actual migration) just ask.

Don't forget to think about a e-mail anti-virus solution as well. We find that an ISA server does a pretty decent job of firewall/router/e-mail scanner for a small to medium sized company.

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Some more info

by LordInfidel In reply to New Exchange Installation

Some others touched on this.... I will add my 2 sense, since I administer exchange in a enterprise setting.


1. Your ISP has given you 1 routable IP (your router)

2. Your network is private (10.x.x.x) and nat'd viayour ISP's firewall/proxy/router.
2a. You do not control firewall/proxy/router, your isp does.

3. DNS is ISP hosted.

4. You own your own registered domain name.
4a. Your ISP maintains your zone records.


1. Contact ISP... Tell them that you want to host your own mailserver.

a. They will need to point the MX record for your domain name(s)to your routable IP (firewall/proxy/router).

b. They will need to map port 25 at the proxyserver to your pvt address of and must allow inbound and outbound to that address.

2. If all of your users are internal I suggest reccomend not using POP3 accounts. Use the Outlook configured for Exchange. Keep all of your mail on ther server. You spent the cash, take advantage of it's power.

3. In the IMS, on the connections tab, specify use DNS. Do not forward message to a external host (which is a mail gateway) unless you are relaying your mail to your ISP's mail server. Get their permission first.

If this is your first installation of exchange, I strongly urge you to seek outside help and get the exchange server training book from MSpress. Exchange is fairly complicated and requires a strong knowledge of it. Especially for non-straight forward installations.

Good luck


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Additional- DNS Resolution

by LordInfidel In reply to New Exchange Installation

Just some more tid bits.

Exchange relies heavily on DNS resolution for it's ability to route mail.

It must be able to resolve domain names. This is one of the main key's to a sucessful installation and routing mail.

It also needs a static IP, which you have made allowances for. But it must also have the address of a DNS server. I suggest having a prim and backup.

Some other clarifications for you. POP3 is a type of mail support, just like IMAP and exchange.

SMTP is the underlying protocol used to transfer mail between mail systems.

When a POP3 client sends an e-mail, it connects to it's outgoing SMTP mail server and the mail server then sends it out using the SMTP protocol.

So in a nutshell, think of POP3, IMAP andExchange as client to server. And SMTP as server to server. Sort of like IP routing from router to rourter.

Again, have fun.

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