How to Determine What Subnet an IP Address is on - 40,000 IP Addresses

[RobertIngles]

Hello all;

I have been tasked with scheduling a software push by subnet. I have been given two pieces of information - a list of subnets and subnet mask bits, and a list of ip addresses:

Table 1 has about 1400 subnets and subnet mask bits, table 2 has about 40,000 ip addresses.

I took a course in subnetting years ago and can calculate ip addresses manually for a subnet however I have days to set this up not years...is there a simple calculation/method to determine which subnet each ip address belongs to with this number of IP Addresses?

Thanks for your help!

 

[SweetRevelation]

If you can convert to binary and do a bitwise AND operation between the mask and the IP address you will get the subnet.

Sounds like a pain in the ass, I don't envy you.

 

[RobertIngles]

Maybe I could go another way?

Is there a way to generate the available IP addresses for a large group of subnets? - that way I could do a comparative back to the list.

 

[robertjo24]

Solarwinds has a free subnet calculator that will list all the available IP addresses for a particular subnet and mask. Just enter the IP address and mask and it will create a full list.

I think you can export to Excel as well.

 

[VinceWhirlwind]

There are loads of online ones available, eg

http://www.subnet-calculator.com/