Actually I have done most of those things at one time or another. I'm not saying IPv4 is simple (especially if you want to do complex things with it) but it wo

Actually I have done most of those things at one time or another. I'm not saying IPv4 is simple (especially if you want to do complex things with it) but it works well when configured correctly and is simple enough to be deployed in businesses of all sizes as well as home networks. I didn't get involved with networking much until shortly after most other protocols were rapidly disappearing but the fact that IPv4 replaced IPX, DECNET, AppleTalk, etc in only a few years time suggests that it probably wasn't that much of a nightmare to set up, even in it's early days. My concern with IPv6, based on this post, is that it may have lost some of the robustness and relative simplicity of IPv4. I mean layer 3 <-> layer 2 address mapping is fundamental to any network and if that's breaking with IPv6 it could be a pretty serious issue.