SBS 2003 using routed IP

[pcoxwell]

Hello there,

I am completely new to networking so please excuse me for the lack of technical knowledge that i have to explain my problem.

I am installing a small office network; we are a production company that is starting to expand so want to put a strong IT infrastructure in place ready for growth over the next year.

We have opted to use Windows Small Business Server 2003. Our ADSL connection features 8 fixed IP addresses, 5 of which are available for allocation. Our connection comes into a Draytek 2600We modem/firewall/router which then connects to a switch and the switch, into which the client machines are connected, connects to the server machine.

I have no problem with setting up the network, installing software, client profiles etc. But my problem is this...

I want to assign one of my IP addresses to deliver e-mail. However I have absolutely no clue how to do this. What settings does the server machine need to have? Does the server machine need to have its Network Device set to the fixed IP address? I have been hunting for days but to no avail.

I know that there is an option to change the server IP address but i'm not sure if this is right.

If someone knows what I need to do, please help! I need an idiots guide to doing this, sorry!

Many thanks in advance for your help.

 

[Jpoandl]

On the firewall, you need to create a rule that specifies mail traffic is allowed inbound to your Exchange servers internal IP address.

Mail traffic is port 25.

So you need to do the following.

1) allocate one of your public IP addresses for your mail server. so let's say 64.56.43.20 is your public IP address that you choose.

2) register 64.56.43.20 with your ISP and have them create an "A" record for you. You need to tell them a NAME and an IP address: mail 64.56.43.20 (the name of the server can be made up...it should'nt be the actual name of your internal mail server)

3) you need to register an MX record with your ISP too. MX=MAIL (where mail is the "a" record that you made up in step 2.

At this point, you registered Internet domain name should have an A record and an MX record.

domain.com
mail 64.56.43.20
mx 64.56.43.20
or mx mail.domain.com

4) create a firewall rule to allow mail traffic to flow into your internal exchange mail server. Mail, by default, flows over port 25

so, your rule must allow ANY ---> exchange server internal
IP

Lets say, your interal mail server has an IP of 192.168.5.11

your rule must allow ANY --> 192.168.5.11

Once these steps happen, you should be able to receive mail internally.





Joseph L. Poandl
MCSE 2003

If your company is in need of experts to examine technical problems/solutions, please contact

http://www.NJCOMPUTERNETWORKS.com

(Sales@njcomputernetworks.com)

 

[dkediger]

With SBS/Exchange, you only need 1 public IP address as long as your firewall/router supports NAT/private IPs internally and your ISP manages your public DNS. They can set up an MX DNS record for your mail to point to your firewall/router as well as register your public domain name. From there, you tell the router that all IP port 25 traffic (SMTP mail) goes to IP address of your server.

Ideally, your router should not be connected to the switch with the clients. A better setup is to have 2 network cards in the SBS server - one for the internal LAN which would connect to the switch, and one for the external WAN that only connects directly to the firewall/router.

Each server NIC would then have a different private IP subnet: such as 10.0.0.x/255.255.255.0 for the WAN and 192.168.1.x/255.255.255.0 for the LAN. To receive mail in Exchange this way, you tell router/firewall to forward to the external WAN address of the server.

In SBS you run the Configure Email and Internet Connections Wizard under the Internet and Email page in the SBS Server Manager. It will step you through the process and allow you to assign network card IP subnets.

 

[pcoxwell]

Thank you to you both for your responses, I have done this and hopefully things should be successful when the IP addresses go live on Thursday. There is one thing I am having difficulty at the moment; I know this is probably the wrong place to post this but just wonder if anyone has any idea about how to do this:

I know that I have to change the MX Record/Tag in order to forward mail for my domain to the IP address. My site is administered through cPanel and there is an option to look at the MX records. My site is called oscada.com, and I can select it as the record i wish to change. Note: You must enter a FQDN (Fully Qualified Domain Name) as the MX destination. However, below it is this information:

Warning: Changing your MX to something besides mail.oscada.com will prevent the server from managing your mail.

Does this mean that the e-mail for my site will be re-directed to the IP i assign to the MX record but will render mail.oscada.com inactive?

Being new to this it's all a little confusing and feel like a little fish in a big ocean!

Many thanks in advance for your help on this!

 

[pcoxwell]

I've just read up on the cPanel site and it says 'You can only change the entry to a domain name (e.g. yourdomain.com), not an IP (Internet Protocol) address.'

Any suggestions on what I need to do? My host says this is the only way to do it...

 

[dearingkr]

See Jpoandl's response for your answer.
He gave you excellent advice.

Evidently your dns records already have a 'A' record for mail.oscada.com

You just need to change the IP address of that record to whatever public IP address you're going to use.

MCSE CCNA CCDA

 

[Jpoandl]

Does this mean that the e-mail for my site will be re-directed to the IP i assign to the MX record but will render mail.oscada.com inactive?"

Yes, I think this is true. Does mail.oscada.com already exist? Is your registered domain name oscada.com? Does your isp currently host your e-mail for you on a web page or through POP mail? If you answer these questions with yes, then you will render the current way e-mail gets delivered useless and will be pointing all mail to your internal Exchange server. This is probably what you want to do if you are planning to use MS Exchange server. If you have MS Exchange, there is no reason to use the ISP mail server any longer.

But if you are unsure, call your ISP and they will help you with this...



Joseph L. Poandl
MCSE 2003

If your company is in need of experts to examine technical problems/solutions, please contact

http://www.NJCOMPUTERNETWORKS.com

(Sales@njcomputernetworks.com)

 

[pcoxwell]

Thank you so much for the advice you've posted here, I've now had my host updated the A record for Mail to point to the IP address and have added the rule to my firewall...

Any idea how long this takes to kick in or should it be an instant process? So far I've been waiting around 12 hours.

Many thanks

 

[Jpoandl]

You can use the tool NSLOOKUP to determine whether the change has propagated.

NSLOOKUP is a built in tool that queries DNS. You can look for your "a" record and "MX" record. From a command prompt type NSLOOKUP to enter the utility.

For example:

C:\>nslookup
Default Server: localDNSserver1
Address: 10.10.10.1

> mail.company.com
Server: localDNSserver1
Address: 10.10.10.1

Name: mail.company.com
Address: 65.34.32.23 <--- this is the response

To look for MX records, while in the NSLOOKUP utility, type:

> set type=MX
> acme.com <---type your domain name to see MX records
Server: localDNSserver1
Address: 10.10.10.1

acme.com MX preference = 10, mail exchanger = gate.acme.com
acme.com nameserver = dns.thinkbank.com
acme.com nameserver = net.indra.com
acme.com nameserver = server.indra.com
gate.acme.com internet address = 216.27.178.28
dns.thinkbank.com internet address = 66.117.159.5
net.indra.com internet address = 204.144.142.1
server.indra.com internet address = 204.144.142.2

-later

Joseph L. Poandl
MCSE 2003

If your company is in need of experts to examine technical problems/solutions, please contact

http://www.NJCOMPUTERNETWORKS.com

(Sales@njcomputernetworks.com)

 

[dearingkr]

DNS changes can take up to 48 hours to propagate throughout the internet.

MCSE CCNA CCDA

 

[pcoxwell]

Hmmmm,

I have set had the changes made with the DNS so that the mail record points to an external IP and the MX record points to mail and setup the firewall rule to allow all external traffic to point to the internal IP but it doesnt want to work!!?? Any ideas what I've done wrong?

 

[dearingkr]

Just tested your connection, works fine.

Pinged mail.oscada.com
Resolved to 82.69.189.121
Pings answered.

Telnet 82.69.189.121 25
Connection established
Answered by an Exchange server.

You should be good to go.

MCSE CCNA CCDA