The invention relates to a method for ascertaining an address for a peer communication terminal which holds a file. If peer communication terminals (P1, P2) repeatedly send request messages (N1, N2) to a first index server (IS1), with the request messages relating to a file (D) and with the first index server (IS1) not storing an address for a peer communication terminal which holds this file (D), then an interrogation device (AE) automatically ascertains an address (IP3) for a peer communication terminal (P3) which holds this file (D). This address (IP3) is transmitted to the first index server (IS1) by the interrogation device (AE). The first index server (IS1) then stores this address (IP3), so that when a further request message relating to this file appears the first index server (IS1) is able to provide this address (IP3) in response to the further request message.

@{patent:20050267990,
  title     = "Method for ascertaining an address for a communication terminal",
  number    = "20050267990",
  author    = "Andersen, Frank-uwe (Berlin, DE), Meer, Hermann De (Passau, DE), Dedinksi, Ivan (Passau, DE), 
    Hossfeld, Tobias (Wurzburg, DE), Kappler, Cornelia (Berlin, DE), Maeder, Andreas (Wurzburg, DE), 
    Oberender, Jens Oliver (Passau, DE), Tran-gia, Phuoc (Wurzburg, DE), Tutschku, Kurt (Gerbrunn, DE)",
  year      = "2005",
  month     = "December",
  url       = "http://www.freepatentsonline.com/20050267990.html"
}