> it would be a very broken implementation, but not something > that harmed the Internet or even anyone else whose applications worked > properly. At most it would harm its own user, who I assume would quickly > dump it. I don't think harm to the Internet is the bar for MUST. If your implementation would generally be considered broken if you did X, then I think that rates a MUST NOT X. It's often a bit of judgment whether to use MUST NOT or SHOULD NOT, and we have some latitude in making that judgment. I agree with PSA and MNot that this case should be MUST NOT. Barry _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf