Newbie Help please (2621)

[redeyes1965]

If i explain my task, could someone please help me with the congiguration.

Here goes.

Have had a 256k dsl link installed for internet access. With a single pc attached i can access to the internet great.

Now i want to put a 2621 router in between the isdn and my network to act as a firewall.

internet gateway is in the 217.xxx.xxx.xxx range with a subnet of 255.255.255.240 so i presume that i would configure ethernet 01(outside) in this range.

i want to gain access using the range 197.x.xxx.x
with a subnet of 255.255.255.0 so i presume i need to configure ethernet 00(inside) in this range.

What else do i need to do to ensure firewall protection from the internet + is it possible you could show me an example config that does this?

Thanks for your help in this matter

Tim

 

[rburke]

Well, it depends on what IOS version you have. Post your IOS version. What do you mean by:

"i want to gain access using the range 197.x.xxx.x
with a subnet of 255.255.255.0 so i presume i need to configure ethernet 00(inside) in this range."

Do you want to use the 197.x.x.x/24 for your interal IP range? The only way you could do that is if you owned that entire Class C network. For your internal IP addresses you'll need to stick with the private IP ranges using NAT. 10.0.0.0/8, 172.16.0.0-172.16.31.0.0, and 192.168.0.0/16. I think those are the right ranges, just off the top of my head. Let us know some more info about your setup, and if you have any "real" IP's other than the one from your DSL service.

burke

One more question, you said you have 256k DSL connection, but then you said you wanted to setup the firewall between the ISDN and the network.... Do you have 2 connecitons, or was it a mistake. Let us know....

 

[redeyes1965]

Thanks for getting back, i realy appreciate your help.

IOS = 12.0T , although i made a call today to our supplier about upgrading this.

I understand what you are saying about the inside ip range (my inexperience has shone through) let make that a 192.9.XXX.X then.

Im confuse a bit as to your last question. I think the answer is that we have an isdn router that was supplied when the isdn adsl was installed and yes this has several sockets 4 to be exact.

thnx

tim

 

[rburke]

Ok, I found the private IP ranges:

A 10.0.0.0-10.255.255.255 (10.0.0./8)
B 172.16.0.0 172.31.255.255 (172.16.0.0/12)
C 192.168.0.0 192.168.255.255 (192.168.0.0/16)

I was pretty close... But anyways, you won't be able to use the 192.9.x.x because it isn't in the private IP range. You'll need to choose another...

My final question was supposed to ask if you have both a ISDN line and ADSL line going to the router, or if there was only a ISDN or only a ADSL. Sorry about the confusion..

burke

 

[redeyes1965]

thats ok its my lack of understanding.

its not isdn its adsl it was my mistake.

thnx tim

 

[rburke]

Tim,

So you have just ADSL to your home? or office? Also, do you have a static IP address, or is it dynamic. You can usually tell if it is static because you'll be paying for it, and you'd have to configure your computer for it. Also, you said there is one PC, are there any other computers or devices that would require IP addresses? It would be a pretty easy setup if there was only a few devices that needed IP addresses. Let me know.....

burke

 

[redeyes1965]

Office. I did have to configure the pc for it, so guess static. Although when the router is in place i would like a translation so that the pc's ( about 20 ) will be in a different range than the isp gateway. Hence my confused messages about private ip ranges

Thnx

Tim