反垃圾邮件http://cbl.abuseat.org 回邮件给我说我的HELO指向的是我邮件服务器的IP地址
Use of a bare IP address in the HELO is a violation of
RFC2821 section 4.1.1.1, which says that the HELO value MUST
be either a fully qualified domain name (such as "mail01.example.com")
or an IP address enclosed in square brackets (such as "[118.126.***.***]").