If calling in the US ...
1)The carriers can not provide you with a list of DNC numbers that will stop your client from being fined. ONLY purchasing the required area codes/states/entire list from
https://telemarketing.donotcall.gov/ will provide this protection IF you follow the Laws which are (conveniently?) provided/referenced/included in the site signup. On a lighter note, your client can get FIVE free area codes just for signing up (and the laws will be part of the signup process ...)
2) Putting hundreds of thousands of entries in the DNC list table in Vicidial will bring down the server. The DNC check happens with each call and each hopper load. Comparing the entire public NDNC list against millions of prospects with every call is not viable even with the most powerful database server. Instead, pre-process leads before uploading them and then check them again nightly or at the very least Monthly (which is how often your client is required to update their National NDNC list in the US)
3) We have a product designed to block dialing until after the check which also automatically checks all leads nightly. To maintain the system, you download each state or area code list from the NDNC site (as often as you like, but monthly at the longest) and upload them to our system in your dialer. Nothing else, takes only as much time as logging in, downloading, uploading ... and forget about it.
Vicidial NDNC Nightly Checker