Anders Wandahl has self-archived "Not Served on a Silver Platter! Access to Online Mathematics Information in Africa" in arXiv.org.
Here's an excerpt:
The "truly free" resources listed in the table [e.g., open access journals] above are free to anyone and anywhere. Resources provided by other programmes and initiatives, which are described below [e.g., HINARI], are also free to end-users in all or most African countries. However, there is an importance difference between these two groups of resources. The second group requires some sort of authentication before the user is allowed access. . . .
In order for the IP number control system to work smoothly, the public IP number(s) should be fairly stable. In Africa, this is not always the case, since a change of the Internet Service Provider (ISP) also usually means a change of the IP number. African institutions sometimes see an advantage in negotiating terms and prices with a new Internet Service Provider now and then, in order to find a more favorable deal, but this means that the new IP numbers must be supplied to all journals and publishers before access is reestablished.
To complicate this picture a little further, there is a distinction between static and dynamic IP numbers. In general, there is a world-wide shortage of IP numbers. In order to cope with this situation, the numbers are sometimes assigned to universities and institutions in a dynamic as opposed to static way. A dynamically assigned IP number may change any time (even though they usually are pretty stable over time). A static number is assigned once and is not supposed to change as long as you have a running contract with an Internet Service Provider, which makes them better for authentication purposes. The flip-side of the coin is that static numbers are more expensive.