Requesting rDNS means "I don't want to receive email from Africa".
Having an rDNS entry for a host doesn't mean you know if it is/isn't in Africa, to any higher degree of certainty than when you just had the IP address.
What he was pointing out her is that a majority of African ISPs do not even have the ability to assign rDNS to their address space. This is an unfortunate fact which should get somewhat better as a result of ARIN policies 2002-3 and 2003-15. I don't know to what extent those policies have helped yet, but, at least it is much easier for African ISPs to get direct allocations now. In essence, it is virtually impossible for a small-medium business in Africa to set up a mail server and have rDNS entries created for it because their ISP doesn't control the IN-ADDRs and the imcumbent Telco doesn't want to do anything they don't absolutely have to for the competitive ISPs. Owen -- If it wasn't crypto-signed, it probably didn't come from me.