02-12-2012 01:23 PM - edited 03-04-2019 03:14 PM
Hi, I'm hoping someone could point me in the right direction. I work for a very small company so it's down to me to do everything technical, now whilst new things usually come down to me looking on youtube, the current problem has stumpted me totally. I don't know where to start looking.
The situation we have is, BT is puting in a leased line (EFM) connection with a managed router. We (I) have specified we need 90 ip addresses for our customers (1 per customer). What I want to do is forward all traffic from 1 incomming IP address to an internal IP address but I have no idea how to achieve this. I have a couple of Cisco routers 2611xm. Any points in the right direction would be very appreciated.
Regards
Dave.
02-12-2012 03:43 PM
Hi Dave,
If those 90 ip addresses are part of a single subnet you can use nat to translate from one public ip to the subnet.
Example
int Fa0/0
ip address 192.168.1.0 255.255.255.128 -it gives you 126 ip addresses for customers
ip nat inside
no shut
int Serial0/0
ip address x.x.x.x x.x.x.x -public ip assign by ISP
ip nat outside
no shut
access-list 1 permit 192.168.1.0 0.0.0.127
ip nat inside source list 1 interface Serial0/0 overload
The last command allows all customers to use the single ip address configured on serial interface to go outside of LAN. It does that by translating the private ip address to public ip address to go out surfing the big Internet.
Hope this will help you
Eugen
02-13-2012 01:43 AM
Eugen that is great thank you so much, I was at such a loss as to how to accomplish it.
I have another question if you can answer this I will be a happy man. I won't go into details of the product because it isn't a cisco product, what I would like to do is virtually the reverse of the solution you previously gave me. What I would like to do is this
point a application to a local IP address which then forwards all traffic to an external IP address and any return traffic route back to the local ip address so the application pointing to it can receive it. I really hope that makes sense. Can this be accomplished with a router? I would like to be able to have multiple of these re-routes
Regards
Dave.
02-13-2012 03:13 AM
You have to use an extended access list.
Change the access list above to
Example
access-list 101 permit tcp host 192.168.1.1 80 host x.x.x.x eq 80
it permits port 80 communication between one source and one destination
Eugen
edit
You can find more info here
http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtml
02-13-2012 03:38 AM
You are an absolute star, thank you so much.
Dave.
02-13-2012 03:49 AM
Glad to help
Eugen
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