Originally Posted by
llondel
That would be
RFC3397 specifying how DHCP option 119 is encoded, I assume?
It was earlier than that. My work was in 1998-2000.
As for it being proposed by MS, the cynic in me wonders if that was because they had a hole in their implementation whereby it might try to erroneously re-allocate an address. I'll let them off if so, it is good defensive programming and handles the case where someone's configured a static IP in the middle of the dynamic allocation pool. On the other side of the coin, there's an interesting denial-of-service attack there if you've got something sitting on the network that will respond to such pings from the DHCP server, such that it thinks the entire pool is allocated
You'd be right to be cynical. At that time, Microsoft had been kicked hard by a lot of heavyweight for lack of RFC-compliance in a lot of the things they were doing, so it became apparent that someone inside Microsoft had handed down an edict saying they were going to drive compliance through RFCs, which essentially meant them doing what they wanted and proposing it as extensions to existing RFCs.