Complex redistribution can be quite a challenging task to encounter studying for the CCIE R&S lab. There doesn’t seem to be that many clearly define general rules out there. So I thought why not dissect each individual case that could cause tricky redistribution problems.
RIP and OSPF are a perfect example of two protocols that when they meet, something will go wrong by default. The reason that these two protocols are so prone to problems is for 1. RIP has no concept of an external routes and 2. OSPF has the same AD for internal and external routes.