IE does this, but Firefox doesn't and never has. See: https://bugzilla.mozilla.org/show_bug.cgi?id=399324 https://bugzilla.mozilla.org/show_bug.cgi?id=399324

IE does this, but Firefox doesn't and never has. See: https://bugzilla.mozilla.org/show_bug.cgi?id=399324 https://bugzilla.mozilla.org/show_bug.cgi?id=399324 https://bugzilla.mozilla.org/show_bug.cgi?id=245609 https://bugzilla.mozilla.org/show_bug.cgi?id=245609 Chain cert problems can still go unnoticed in Firefox, however, because Firefox does cache chain certificates that it encounters browsing other sites. In any case, the relevant RFCs require servers to send a complete chain.