Today our email forwarders started getting this from yahoo.com
mail handlers:
553 Mail from 216.220.40.247 not allowed - VS99-IP1 deferred - see
help.yahoo.com/help/us/mail/defer/defer-02.html (#5.7.1)
Connection closed by foreign host.
Us too. And more than one ISP that I have seen (for example, iglou.com
mentioned that one of their boxes was being blocked)