X-Originating-IP
The X-Originating-IP (not to be confused with X-Forwarded-For) email header field is a de facto standard for identifying the originating IP address of a client connecting to a mail service's HTTP frontend. When clients connect directly to a mail server, its address is already known to the server, but web frontends act as a proxy which internally connect to the mail server. This header can therefore serve to identify the original sender address despite the frontend.
Format
The general format of the field is:
X-Originating-IP: [198.51.100.1]
Origins
In 1999 Hotmail included an X-Originating-IP email header field that shows the IP address of the sender.[1][2] As of December 2012, Hotmail removed this header field, replacing it with X-EIP (meaning encoded IP) with the stated goal of protecting users' privacy.[3]
See also
- Internet privacy
- List of proxy software
- X-Forwarded-For
References
- ↑ "Q&A: Fighting Spam at MSN Hotmail". Microsoft.com. 1999-09-22. http://www.microsoft.com/presspass/features/1999/09-22spam.mspx.
- ↑ Declan McCullagh (2001-06-16). "The Wrong Way to Do Dirty Tricks". Wired.com. http://archive.wired.com/politics/law/news/2001/06/44567.
- ↑ what does X-EIP mean in an email message source
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