Hopefully this should be a simple question ... (Note: Akamai used as a generic CDN name in the context of this email and could be any CDN provider) Context: regulatory filings where wireless carriers states that zero rating of certain selected streaming music is done based on the "from IP" in packets coming into its network. When a content provider such as jf_music.com (fictitious) makes use of one or more content distribution networks, does the "from IP" in packets belong to the CDN, or to jf_music.com ? (if Akamai uses IPs provided by jf_music, this has inteteresting routing questions). If I setup such a service with Akamai, does Akamai provide me with an authoritative list of IPs that will be generating my traffic in various cities ? Are these IPs stable or would they typically change fairly often as Akamai builds more nodes etc ? And do various CDNs have very different implementations ? And in fictitious case of jf_music.com hiring Akamai, would the Akamai server(s) have a dedicated IP for jf_music in each city (or re-use same IP via anycast) or would the CDN servers use the same IP address to deliver multiple services from totally different content providers ? (Considering BGP routing limits , I have to assume that routing of individual IPs can't be done). I need more of a sanity check on this.