Remote Connection to a B class Network Through C class Network

[Jameel Ahmed_1]

Hi, I have network based on C class (192.168.0.1 - 254) and using DSL Internet which also supports only C class. One of my PC is using a software that supports only B Class network (Ip: 72.20.20.11 Subnet:255.255.0.0). So far things are ok and both networks are working properly. But now i have some problem in B class network and I want to get the support from my software vendor who will access the PC through internet. Since that PC is on B class it cannot access internet and If i change the IP address to (192.168.0.?) he wont be able to use the software. Can anybody guide me how can He access the system through internet without changing any IP address

[Olaf Borowski]

Jameel,

Since you are using 192.168.x.x addressing, you have to have a devices that does "NAT" for you anyways. This address space doesn't get routed in the Internet.
I think you issue is "private" vs. "public" IP addressing. Per RFC 1918:
10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
These are the ip address ranges for private use.
Back to your question.... I am pretty sure, that you have some kind or firewall or router that get's your PC's to the internet via "port address translation" meaning, all PCs get mapped to one public address when they go out to the internet (IP address of DSL connection). If you have a firewall, put the PC using the special software in the DMZ.

What is your network topology? Where does this PC reside today (it is reachable via the internet already).

Olaf

[Jameel Ahmed_1]

Hi Olaf,

Thanx. I got my problem solved. It was so simple. I just had to add another IP of C class & gateway in advance IP setting of destination PC. This helped in accessing software with 72.20.20.11 IP address and internet with 192.168.0.9 IP address.

Thanx for your time

Regards

Jameel