How is it possible to get a mail with a date from 1905??

[devnull]

Hi,

A friend has sent me an email in which he has managed to trick the date.
As in:
From: myfriend <friend@friendsisp.com>
Date: Jan 11, 1905 2:15 AM
Subject: How did I do it?
To: Me <me@gmail.com>


In the Gmail Inbox folder, the date shows correctly, with the current day in March 2008.

As you know, you cannot get any more headers than the ones that gmail briefly presents you when you hit "Show Advanced".

If I understand it correctly, my friend's email SMTP server should be the one tagging his email with the actual date.

Also, according to
Unix time - Wikipedia, the free encyclopedia
you cannot set the date on your computer before January 1, 1970 on ANY computer. For Windows XP is even worse, this date is January 1, 1980.

Hence, does anybody know how could have he done this?

[leftybogs]

hmm.. I didn't know that too... interesting..

[andrew247]

Unix time is a 32 bit signed integer (signed meaning that the first "bit" of the number is used to represent whether the number is positive or negative).
So, if you change the first bit of the unix timestamp to be a 1, it will be interpreted by most computers as a negative number, and so you get the date as "1st January 1972 minus the number of seconds" (i.e. it will be before 1970).
Google obviously ignores the signed bit and just interprets the rest of the number.

[[ugly_cat]]

if.,surely received it.,so interesting error.

[Cryxellis]

Originally Posted by andrew247

Unix time is a 32 bit signed integer (signed meaning that the first "bit" of the number is used to represent whether the number is positive or negative).
So, if you change the first bit of the unix timestamp to be a 1, it will be interpreted by most computers as a negative number, and so you get the date as "1st January 1972 minus the number of seconds" (i.e. it will be before 1970).
Google obviously ignores the signed bit and just interprets the rest of the number.

Really interesting and I find it really cool ^_^