In this scenario it wouldn't matter who assigned the addresses to you. You will be advertising those addresses via BGP to both ISPs, who in turn should propagate those advertisements. I believe there are situations where ISP2 would need some sort of verification from ISP1 that it's okay to advertise that block but I'm not aware of the details.
An interesting situation that can occur is when the ISP who assigned your addresses doesn't advertise your specific addresses but instead aggregates them. Because the second ISP will be advertise a more-specific match the whole world will try to reach you through ISP2. So, it's important to verify that all of your ISPs are advertising your specific addresses. That's more than what you asked, but I've been rambling a lot lately. John >>> "Steven A. Ridder" 5/2/02 2:28:04 PM >>> Here's a question I can't seem to answer. I came up with a scenario in my head, and now I can't find a solution. Example: I have a dual homed network via BGP. I have ISP 1 and they give me 209.21.220.1/20 for use, and ISP gives me 199.33.23.1/21. Say I use the 209.x.x.x for my web servers, mail server, etc, and advertise that back out to the Internet via ISP 1 (the ISP that assigned me the block) and in DNS. I'm assuming ISP 2 will not advertise that block for me, as it's ISP 1's block. So, now the whole world knows to get to me via ISP 1. Then let's say ISP 1 goes down, how would the world know how to get to me, if they only knew how to get to me Via ISP 1 and it's IP's? -- RFC 1149 Compliant Get in my head: http://sar.dynu.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=43166&t=43163 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
