1) Log in to Gmail
2) Open the message you'd like to view headers for.
3) Click the down arrow next to Reply, at the top of the message pane.
4) Select Show Original.

The full headers will appear in a new window, there you will find Received: from [144.76.120.56] by mandrillapp.com

If you cannot able to get the IP Address, copy and paste here.

144.76.120.56 IP address information
Passive DNS replication
The following domains resolved to the given IP address.
2014-02-08 www.localbitcoins.com
2013-11-19 localbitcoins.com

Are you getting the same IP Address ?