[kimbert]

Hi everyone!

First time here and have a question. I know not much about setting up a corporate networking that have some serve that want external to access such as Web server, email server, etc.

What I got!
- ADSL2+ modem. It can set up NAT for external to access my web and email servers, which I have no problem if I use a static IP that gave by my ISP.
- Some work stations access the internet through the ADSL2+ modem.
- Some servers that host web and email servers.
- A block of 4 IP addresses given from my ISP

What I have done!
- All machines can access internet via ADSL2+ modem using a static IP given by the ISP.
- I changed a DNS record for one additional IP address to be my web site (4.3.2.1.mywebsite.com)

What do I need to do? if what I want is...
- I want Internet to access my web and email servers using another IP address I have instead of a default static IP.

If my question make no sense that is because of I really don't know how to ask. So, I don't know what key word should I type into a search field.

FYI:
- ADSL Modem ZyXel P-2602HWL-D1A (2 active VOIP lines connected)
- I also have some spares Modem/Router (Draytek, NetComm) from my past ADSL settings.
- Running Windows 2003 servers
- Server hardware are server category HP Prolaint
- Only ADSL modem for a router, some dump switches.


I thank you in advance for anyone that can help me out.

[leroys1000]

You would probably need to use another modem for
the web and email servers and assign them the IP
you want to use.
That should also reroute that traffic off the other modem.
You would need 1 modem for each IP connected to and
configured for the computer you need to connect.

[kimbert]

Thank you so much, leroys1000 for helping me head to the right direction.
I have more questions:

Basic info:
static IP for ADSL: 100.101.102.1
Additional block of IPs: 100.101.200.1 - 100.101.200.4

Diagram:

pc...pc (192.168.2.1 ... 192.168.2.255)
|
|
|
switch
|
|
|
adsl+router 100.101.102.1 <---------------> internet
NAT (to set port/ip forwarding for internet IPs to local IPs)
internet IP: 100.101.200.2 <-> intranet IP: 192.168.1.100 (web server) <--connect to ADSL modem/router--> router 1 - IP: 100.101.200.2 <---> server local IP: 192.168.1.100
internet IP: 100.101.200.3 <-> intranet IP: 192.168.1.101 (email server) <--connect to ADSL modem/router--> router 2 - IP: 100.101.200.3 <---> server local IP: 192.168.1.101




My ADSL Modem has ability to set up NAT as following types:
• One to One: In One-to-One mode, the ZyXEL Device maps one local IP address to one global IP address.
• Many to One: In Many-to-One mode, the ZyXEL Device maps multiple local IP addresses to one global IP address. This is equivalent to SUA (for instance, PAT, portaddress translation), ZyXEL’s Single User Account feature that previous ZyXEL routers supported (the SUA Only option in today’s routers).
• Many to Many Overload: In Many-to-Many Overload mode, the ZyXEL Device maps the multiple local IP addresses to shared global IP addresses.
• Many-to-Many No Overload: In Many-to-Many No Overload mode, the ZyXEL Device maps each local IP address to a unique global IP address.
• Server: This type allows you to specify inside servers of different services behind the NAT to be accessible to the outside world.

Firewall that can be setup within my ADSL modem.

- I believe that I can use other ADSL Modem that has router built-in to be a router for my server, correct?
- Each router must be able to route traffic to the ADSL Modem, so they can go to Internet, correct? How can I do that in my router (ie., through NAT?)?
- Can you please look into the network diagram and point out if there is anything incorrect? Much appreciate if you can help me with some advice.

Thanks so much.

[leroys1000]

From what I see,the map looks ok.
Looks like you have 1 modem to one router for each server.
You should have full bandwidth for each system as they are not sharing.
The one to one should be fine as long as you are only
using one IP on the server
If using more,use the multiple.
You shouldn't need overload as you are using a dedicated
connection for each and don't need load balancing.
Make sure the proper ports are open on the routers.
You can use the modem/router or connect the modem directly
to the sever.
The router is only needed if the are multiple local network connections.
Just make sure you have an adequate firewall and antivirus
on the server and only allow ports that are required.