检测公共IP地址是动态的还是静态的 [英] Detect whether public IP address is dynamic or static
问题描述
有几个电子邮件服务器拒绝使用公共动态IP地址连接客户端。例如，许多接收电子邮件的smtp服务器只接受与具有静态IP地址的客户端的连接，以避免从具有动态IP地址的计算机直接发送的垃圾邮件。
There are several email servers refusing connections of clients with public dynamic IP addresses. For example many smtp servers receiving emails only accept connections to clients having static IP adresses to avoid spam emails which are directly sent from computers having dynamic IP addresses.
当我查找时使用谷歌的答案我只发现信息说无法区分静态/动态地址。那么电子邮件服务器如何做呢？是否有任何数据库提供特定IP范围的信息？
When I looked for answers using google I only found information saying it is impossible to distinguish between static/dynamic addresses. So how do the email servers do it? Are there any databases providing information for specific IP ranges?
查看的MX记录t-online.de （德国最大的电子邮件提供商之一）。尝试在具有动态IP地址的计算机上使用Putty（原始模式）连接到 mx00.t-online.de:25 。邮件服务器立即关闭连接，甚至不允许客户端发送任何命令，而没有拒绝具有静态IP的服务器的连接。
Have a look at the MX records of t-online.de (one of the largest German email providers). Try to connect to mx00.t-online.de:25 using Putty (raw mode) on a computer having a dynamic IP address. The mail server immediately closes the connection and does not even allow the client to send any command, while a connection of a server having a static IP is not refused.
或者有看一下SMTP会话的以下摘录：
Or have a look at the following extract of a SMTP session:
220 mailin.rzone.de [joses mi173] ESMTP RZmta 29.19 ready
EHLO Home-PC
250-mailin.rzone.de [joses mi173] greets 87.179.163.89
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-PIPELINING
250-DELIVERBY
250-SIZE 104857600
250 HELP
MAIL FROM:<sender@example.com>
250 2.1.0 <sender@example.com> Sender ok
RCPT TO:<recipient@example.org>
550 5.7.1 87.179.163.89 is a dynamic IP
这是电子邮件服务器德国托管公司Strato的客户，也拒绝访问拥有动态IP地址的客户。电子邮件地址已更改。我使用了 mailin.rzone.de 可接受的收件人地址，因此没有中继问题。
This is the email server for customers of Strato, a German hosting company, which also denies access to clients having a dynamic IP address. Email addresses have been changed. I used a recipient address which is acceptable for mailin.rzone.de, so there is no relay issue.
另外 http://whatismyipaddress.com/blacklist-check 说明如下：
仅仅因为IP列出了特定的黑名单而不是
意味着你发送了垃圾邮件，只是那个特定的黑名单
建议不要接受直接从该IP地址发送邮件。 动态分配的大多数
住宅有线/ DSL IP地址将以
表示它们被列入黑名单，这意味着您应该从
发送ISP的邮件服务器，而不是在您自己的互联网上运行的邮件服务器
连接。
Just because the IP is listed with a particular blacklist does not mean that you are sending spam, just that particular blacklist suggests not to accept mail directly from that IP address. Most residential Cable/DSL IP addresses that are dynamically assigned will indicate that they are blacklisted, meaning you should be sending from your ISP's mail server, not a mail server running on your own internet connection.
推荐答案
这可能是因为使用了基于ISP提供的有关哪些IP地址被授权直接发送电子邮件的DNS黑名单。有关示例，请参见Spamhaus的政策阻止列表。
This is probably the result of using a DNS blacklist based on ISP-provided information about which of their IP addresses are authorized to send email directly. See Spamhaus' Policy Block List for an example.
此信息无法独立发现。参与的ISP必须向DNSBL服务提供有关其网络的信息。
The information isn't independently discoverable. Participating ISPs must provide the DNSBL services with information about their network.
但是，如某些列表的情况，如Spamhaus，在一定条件下，公众可以查询该信息。你无法直接检测IP是静态的还是动态的，但仍然可以检查任何特定的IP。
However, in the case of some of these lists, like Spamhaus, the information is queryable by the general public under certain conditions. You couldn't detect whether IPs are static or dynamic directly, but could still check any particular IP.
你提到whatismyipaddress.com错误地将你当前的IP地址列为静态。使用您的IP，87.179.190.52 他们的黑名单检查工具，我发现他们目前错误地将其显示为未列出由Spamhaus的PBL（以及其他人）。我正在连接的IP被正确地描述为动态的，并列在PBL中，暗示这可能是他们所依据的信息。
You mentioned that whatismyipaddress.com incorrectly lists your current IP address as static. Using their blacklist check tool with your IP, 87.179.190.52, I see that they currently incorrectly show it as unlisted by Spamhaus' PBL (among others). The IP I'm connecting from is both correctly described as dynamic, and listed in the PBL, hinting that that might be what they're basing their information on.
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