wrtie a script/program, to test if email addresses are within a list of CIDR blocks

Hi guys, what's up, Here is the thing, I've a list of huge email list (pure text file) of my subscribers, the format is one email address per line, and I have a text file contains of CIDR blocks which I want to filter. Our goal is to test if the email address' MX record's IP addresss is in the CIDR block. For example, email address abc(at)[login to view URL] (here is the symbol "at", the email address is not allowed in freelancer..), first resolve the mx record of the email suffix "[login to view URL]", may be "[login to view URL]", then resolve the ip address of the record, may be 8.8.1.1, then test if the address 8.8.1.1 is i/n the CIDR block. CIDR block file is each CIDR per line, like: 8.0.0.0/8 [login to view URL] ... Please note: 1. The email list is huge, so the script need to be multi-thread, accpet a parameter as how many thread using when running (say " -c 1000"), our server is 24 Core with 120GB available memory and 100Mbps network connection, so concurrent thread my be 1K~10K. 2. The CIDR file contains 8000 lines, which is 8000 CIDR blocks, so please kindly consider the efficiency/performance of the script. 3. Server's platform is Linux (CentOS 7 64 bit), maybe this work can be done using bash script/ python.. or C if you can.. Target price is 10 USD, I'm sorry it's a little low, it's US Dollor and I'm not in a rich country, thanks a lot. Regards, Steven