I just took a look, and the IP in question (168.131.118.123) is routed to a University in Korea (Chonnam University to be exact).
This is a common tactic of spammers.
1) Use an open relay in Asia to send the spam
2) Forge the 'From:' address, so bounces/hatemail/etc go to someone else
From the headers, it's obvious the email did not originate from you, and any self-respecting network admin can figure that out if they just looked. In short, it happens all the time, nothing to worry about.
Krael
This is a common tactic of spammers.
1) Use an open relay in Asia to send the spam
2) Forge the 'From:' address, so bounces/hatemail/etc go to someone else
From the headers, it's obvious the email did not originate from you, and any self-respecting network admin can figure that out if they just looked. In short, it happens all the time, nothing to worry about.
Krael