Check this RFC for the information you need: http://www.ietf.org/rfc/rfc1166.txt Regards, Mohammed. -----Original Message----- From: Nguyen Thi Mai Trang [mailto:trnguyen@enst.fr] Sent: Monday, June 10, 2002 2:33 PM To: ietf@ietf.org Subject: class E address Hi everybody, I have a question about class E IP address. I read a book which indicate that class E IP address has the following format: 1111 xxxx . xxxx xxxx . xxxx xxxx . xxxx xxxx Thus, the lowest address is 240.0.0.0 and the highest address is 255.255.255.254 Another document I read states that the format of class E IP address is: 1111 0xxx . xxxx xxxx . xxxx xxxx . xxxx xxxx I try to verify in RFCs of IETF about this but I cannot. I read RFC 790, 791, 796 but they do not mention about it. Could you please give me the RFCs indicating the format of class E? In the first case I describe in this message, I wonder why the lowest address of class E is not 240.0.0.1 because the adress with all 1 and all 0 have special meanings (all 0 means "this" and all "1" means broadcast). Thank you very much, Mai Trang