When I try to post an article through nnrpd in inn-2.3.2-5 with two "Cc" headers, it says: 441 Duplicate "Cc" header and rejects the article. While it's true that there are some Usenet headers which can't be duplicated, "Cc" isn't one of them, especially since it doesn't have any real significance in a Usenet article (it appears in my article because I'm both posting and mailing the same message). This is therefore an inappropriate reason to reject an article.
Here is an answer from INN upstream: > As far as I know we're on shaky ground here with regard to having a > specification to follow, but to my eye, we follow the latest USEFOR > draft back to RFC 2822. And RFC 2822 states quite clearly in section > 3.6 that the maximum number of Cc headers is 1. Therefore I don't > believe this is a bug, unless someone else feels otherwise? So I'll close it as WONTFIX, you're the only one who's complaining for it.