我有多个 IP 地址和域，并使用映射将 Postfix 配置为根据发件人地址使用正确的 IP 地址
现在仍有服务器使用伪造的 550 进行应答，但我无法确定原因？从日志和电子邮件标头中我可以看到，正在使用正确的 IP 和域。
摘自master.cf：
example-sender-org unix - - - - - smtp -v
-o smtp_bind_address=11.x.x.x
-o smtp_helo_name=example-sender.org
-o syslog_name=postfix-example-sender-org
电子邮件标题示例：
Received: from example-sender.org (example-sender.org [11.x.x.x])
Postfix 调试日志示例（smtp -v）：
deliver_message: from [email protected]
smtp_parse_destination: example-recipient.org smtp
connecting to example-recipient.org port 25
dns_query: example-recipient.org (MX): OK
dns_get_answer: type MX for example-recipient.org
smtp_addr_one: host mx0.example-recipient.org
lookup mx0.example-recipient.org type A flags 128
dns_query: mx0.example-recipient.org (A): OK
dns_get_answer: type A for mx0.example-recipient.org
begin example-recipient.org address list
pref 50 host mx0.example-recipient.org/10.x.x.x
end example-recipient.org address list
smtp_find_self: not found
smtp_connect_addr: bind 11.x.x.x
smtp_connect_addr: trying: mx0.example-recipient.org[10.x.x.x] port 25...
vstream_tweak_tcp: TCP_MAXSEG 1448
global TLS level: none
< mx0.example-recipient.org[11.x.x.x]:25: 220 mx0.some-hoster-example.org ESMTP (some-other-domain.org) (even more power) Tue, 15 Oct 2013 12:
> mx0.example-recipient.org[11.x.x.x]:25: EHLO example-sender.org
< mx0.example-recipient.org[11.x.x.x]:25: 550-Forged HELO: You are not example-sender.org, please use sender
< mx0.example-recipient.org[11.x.x.x]:25: 550 domain as HELO/EHLO not recipient domain.
> mx0.example-recipient.org[11.x.x.x]:25: HELO example-sender.org
< mx0.example-recipient.org[11.x.x.x]:25: 550-Forged HELO: You are not example-sender.org, please use sender
< mx0.example-recipient.org[11.x.x.x]:25: 550 domain as HELO/EHLO not recipient domain.
附注：我的发件人域的 mx0 未指向相同的 IP 地址...这可能是问题所在吗？我以为 a 记录是必需的...
我发现了这个（第三个答案）： http://community.spiceworks.com/topic/228915-exchange-2007-error-550-5-7-1-helo-and-dns-mx-settings
答案1
事实证明，主机提供商要求您使用 mx0 作为 heloname，所有其他的都被丢弃......