switching T1 line - help

[Murugs]

I am not sure whether this is the right place to post my question.

Our company currently has a T1 service. We are going to switch it next week.

We have a cisco router, Pix firewall and win 2000 server and DHCP enabled and clients get a 10.xxx etc address thru DHCP.

The new T1 company has installed all their equipment and has given me some IP addresses,DNS servers,IP address ranges etc and ask me to change something so that I can switch to the new T1.

I am lost here...Where should I change these settings..is it in the router..does any one know what to look for and change when we switch T1's

regards
MP

 

[ciscotech4]

Which device is handling DHCP?
Do you currently use internal DNS? If so which device handles this?

 

[Murugs]

We use internal DNS and our win 2000 server handles DHCP

regards
MP

 

[ciscotech4]

I would think that your T1 interface IP would change to one of the new ones provided to you how ever your ISP should tell you which one to use as their router will have the another ip on the same subnet as yours. You could then use a public IP on the Ethernet Inferface on the router and have the IP on the PIX on the same subnet as the IP on the Ethernet Interface on the router. The other side of the PIX (LAN side) should stay the same as it is now (should be private). Then your new DNS ip addresses would on your internal system as pointers to the external to the outside. This would allow any IP address that can not be resolved internally to resolve externaly to the ISPs DNS servers. Your DHCP scope should hand out the internal IP address of the DNS server in the scope options.

I think this is right but I may have and probably did make a mistake in my explantion. If so please let me know so I can learn from this as well.

 

[Murugs]

ciscotech4..Thanks for the answer.
I am giving more information which might help.

T1 Line Internet - Cisco Router - PIX Firewall - Hub - W2k server and clients

Our internal LAN has 10.x.x.x addresses and DHCP enabled.

On an internal network machine when I do ipconfig it is

DHCP enabled - Yes
DHCP server - w2k server IP
Default gateway - firewall IP
DNS server - same Ip as w2k server

Also w2k server has 2 NIC's.
When I access the PIX firewall using the web I see something called interfaces and there are 2 entries one says outside and has some different IP address, I guess this is static IP from our ISP and one says inside which shows our 10.x..address.

-Could some one tell me whats the structure of our network.
-Why w2k server has 2 NIC's
-why is the firewall showing the default gateway.
-How is the router configured or how to configure a router.