Yeah, agreed.... I had a customer last week call us because we were "blocking them from an important site". After someone called them they found we could access the website no problem... upon further investigation we found their internal IP space had been numbered as 157.166.226.0/24. When we asked them why this IP was used, they told us that a $200/hour network consultant had upgraded their network last week with new Windows servers, new router, new etc. etc. etc.... and that this new IP numbering "sounded like a good number"... Politely told them they were paying too much and next time call someone who knows what they are doing.... "you got ripped off, sorry about your luck".... Oh, and their internal IP space = www.cnn.com ;) Paul -----Original Message----- From: sthaug@nethelp.no [mailto:sthaug@nethelp.no] Sent: February 2, 2009 1:56 PM To: darcy@druid.net Cc: nanog@nanog.org Subject: Re: Private use of non-RFC1918 IP space
Company A uses public IP block A internally. Company B uses public IP
OK, so we start out with a bad network design then.
No. We start with blocks A and B which are both properly allocated by the relevant addressing authorities.
block B internally. Company A and B later merge, and connect their networks. No conflict, no renumbering needed (at least not right away).
Maybe. What if they both happened to choose 1.2.3.4/8? Is this just a matter of decreasing the odds of a conflict? It still seems like bad network management to me.
My assumption throughout this whole discussion, which clearly has not been understood, is that the public IP block used internally is a properly allocated by the relevant addressing authority. That is, for me, the whole point of using public addresses to guarantee uniqueness. Steinar Haug, Nethelp consulting, sthaug@nethelp.no ---------------------------------------------------------------------------- "The information transmitted is intended only for the person or entity to which it is addressed and contains confidential and/or privileged material. If you received this in error, please contact the sender immediately and then destroy this transmission, including all attachments, without copying, distributing or disclosing same. Thank you."