You get an email from a person with whom you have never interacted before and therefore, before you reply to that message, you would like to know something more about him or her. How do you do this without directly asking the other person?
Web search engines are obviously the most popular place for performing reverse email lookups but if the person you’re trying to research doesn’t have a website or has never interacted with his email address on public forums before, Google will probably be of little help.
No worries, here are few tips and online services that may still help you uncover the identity of that unknown email sender.
#1. Find the sender’s location

Open the header of the email message and look for lines that say “Received: from” followed by an IP address in square brackets. If there are multiple entries, use the IP address mentioned in the last entry.
Now paste the IP address in this trace route tool and you should get a fairly good idea about the location of the email sender.
#2. Reverse email search with Facebook

Facebook has 450 million users worldwide and there’s a high probability that the sender may also have a profile on Facebook.
Unlike LinkedIn and most other social networks, Facebook lets you search users by email address so that should make your job simpler. Just paste the email address of the sender into the Facebook search box and you’ll immediately know if a matching profile exists in the network.
If you are able to locate that person on Facebook, download his profile picture and then upload it to TinEye – it’s a reverse image search engine so you can locate his other social profiles where he may have used the same picture.
#3. Check all the other Social Networks

You can use a service like Knowem to quickly determine if a profile with a particular username exists in any of the social networks.
If the email address of the send is something like green_peas@hotmail.com, there’s a probably that he or she may have created accounts of some other social network using the same alias “green_peas” – put that in knowem.com to confirm.
#4. People Search

Finally, if nothing works, you should try a people search service like Pipl and Spokeo – both services let you perform reverse email lookups but Spokeo has a more comprehensive database than Pipl.
Other than regular web documents, Spoke also scans social networks and even the whois information of domain names to find any bit of information associated with an email address. However, some of the results returned by Spokeo are only available to subscribers.

When you receive an email, you receive more than just the message. The email comes with headers that carry important information that can tell where the email was sent from and possibly who sent it. For that, you would need to find the IP address of the sender. The tutorial below can help you find the IP address of the sender.
 Note that this will not work if the sender uses anonymous proxy servers.
 Finding IP address in Hotmail
1. Log into your Hotmail account with your username and password.
2. Click on the Mail tab on the top.
3. Open the mail.
4. If you do not see the headers above the mail message, your headers are not displayed. To display the headers, * Click on Options on the top-right corner * In the Mail Options page, click on Mail Display Settings * In Message Headers, make sure Advanced option is checked * Click on Ok button * Go back to the mails and open that mail.
5. If you find a header with X-Originating-IP: followed by an IP address, that is the sender's IP addressHotmail headers : name ,In this case the IP address of the sender is [68.34.60.59]. Jump to step 9. 6. If you find a header with Received: from followed by a Gmail proxy like thisHotmail headers : nameLook for Received: from followed by IP address within square brackets[].In this case, the IP address of the sender is [69.140.7.58]. Jump to step 9.
7. Or else if you have headers like thisHotmail headers : nameLook for Received: from followed by IP address within square brackets[].In this case, the IP address of the sender is [61.83.145.129] (Spam mail). Jump to step 9.
8. * If you have multiple Received: from headers, eliminate the ones that have proxy.anyknownserver.com.
9. Track the IP address of the sender