title: IP Spoofing in HTTP Request?
body: <p>I know someone that is able to take a list of emails + ip addresses and
  subscribe each email to an autoresponder (GetResponse / Aweber).
  But the amazing thing is that he can do it with the ip address that's provided
  in the list.</p>
  
  <p>So if he has an email xxx@abc.com and IP 185.252.123.321
  he's able so subscribe this email to the autoresponder but
  if you enter into the autoresponder account and look on the
  lead record, you'll see 185.252.123.321 in the IP address field
  and not the real IP address that the request sent from.</p>
  
  <p>Does someone have any idea how could he do it?</p>