Often there is a need to define from what IP address any given letter was sent to an e-mail. This information contains in the letter therefore there is nothing difficult in learning it. So, come via any browser on the e-mail. For work with parameters of the letter use the full version of the web interface (not PDA and not WAP).
1. Open the message with the letter which sender's IP address you need to learn. For example, if you use mail of Yandex, come into the section "In addition" and click "Properties of the letter".
If you came by means of the web interface of Mail.ru service, find at the bottom of the page the reference "Still" and click it. In the appeared window select the Control headings menu.
When using a mail service of Gmail, find a down arrow near which there is a key to the right of the Answer button. Click it and select "Show the original".
In other mail services it is possible to find the corresponding point in dropdown menus or on the page rather easily independently.
2. After clicking of a certain key you will see the long text (usually web interfaces of mail services open it in a separate tab). Find in it a line of the following format: Received: from domain.name (domain.name [mmm.mmm.mmm.mmm]) where mmm.mmm.mmm.mmm is the IP address of the sender of the letter or message.
If lines of such format a little, look for the IP address in the first of them, except for a situation when the local address of the computer, for example, beginning with digits 192.168 is specified in it. In that case look for the IP address necessary for you in the second line. Save the address, close a tab with the text and only then you leave a mailbox.
3. If you received the message of fraudulent character or it contains any threats, report IP found you in the Department of MIA of the Russian Federation. However you remember that it could be sent via the proxy server or from the computer which owner also does not guess that its machine contains a virus.
4. Never distribute information on the received IP address of the sender of the letter and do not use it for implementation of different actions of destructive character. Do not treat other users as treated you.