gHacks notes that “if you using Gmail, you may notice that the IP address is not included if you use the web service, but that it is included if you use a third party program.” Therefore, it’s important to know this so that you can change your habits accordingly. There is a online service called Email Leak Test, which you can use to check and and see if your email provider is leaking your IP address to recipients. It’s very easy to use:
Click on “Start” on the homepage.
Send an email to the unique address listed on the next page – the subject and body are not required.
Wait a few minutes for Email Leak Test to receive your message, after which the page will automatically update with your results.
If your email is leaking your IP address, then you may want to consider using a VPN, changing email providers or using one of these email encryption tools. via gHacks