I think the key here is that you have to NAT into each provider separately. This really only requires some intelligence internal to the network such that you can choose an outbound route towards an active ISP/link. This works well for outbound only and in reality, choosing outbound paths based on various criteria is simple relative to figuring out inbound load balancing, BGP or otherwise. To add to John N's list of gear on that topic, I'd mention the F5 3DNS as one of the more popular DNS based load distribution boxes. Pete *********** REPLY SEPARATOR *********** On 9/18/2001 at 6:41 PM Tony van Ree wrote: >Hi, > >Wouldn't this also depend largely on the routing etc from each of the >upstream providers. For example, if the address range used is within one >provided via the upstream provider it is likely the routes to others in >that >upstream provider will only come via the link provided by the upstream >provider. > >eg. (I know this example uses private space but it is just an example) You >are given a range say 172.16.20.0/23 by you provider. This fits in the >providers range of 172.16.0.0/16. The provider does not allow it's own >addresses in to its network via another provider (quite a normal >arrangement). It will not be possible then to access a number of sites. > >Just a thought on something I have seen on a number of occasions. Maybe >you >have an answer for this. > >Teunis, >Hobart, Tasmania >Australia > >On Tuesday, September 18, 2001 at 05:15:22 PM, [EMAIL PROTECTED] >wrote: > >> If you do not want to go the complexity of running BGP and you still want >> to multihome your network to the Internet here's how to do it: >> >> Purchase and configure two egresses to the Internet via two different >ISPs. >> Say that both edge routers are Cisco 3640's and both have a Firewall, >say a >> Pix behind them for security. >> >> I emphasize that for this to work make sure both 3640s have at least two >> Ethernet or Fa ports each! >> >> Setup your default gateway on both 3640s to be each respective ISP next >> hop. Setup the default gateway of your Pix to its respective edge 3640 >> router. Setup a vlan on a switch, do not make any routers aware of that >> vlan...its only a local broadcast domain...kind of like using a hub. >> >> Say your primary Ethernet interface on both edge routers is E0/0. Patch >> both E0/1 interfaces on each 3640 to your local vlan so that they can >> communicate, don't forget to no shut these interfaces of course. >Configure >> both E0/1 interfaces so that they are both in the same subnet, use a /30 >> bit mask so that there is never a possiblity for IP overlap.....you may >> totally forget about these interfaces..I warn you..I have on my network ; >> -). Now configure HSRP on Both E0/0 interfaces with each other's E0/0 as >> the stanby IP address. >> >> Your done! If ISP 1 dies, HSRP will kick in and spoof the mac of your >> other 3640. All traffic that hits your edge router pointed toward the >dead >> ISP will be forwarded across your local vlan to your other ISP! >> >> This of course doesn't work if your are running a web server and you are >> NATing simultaneously like 99% of the world, however I have a workaround >> for that. Instead of registering with the A root DNS server the outside >IP >> address of your primary 3640 as the resolution to www.yourwebpage.com. >Pay >> a little extra for a fully meshed ISP to host a static page for you. >> Register this static page with Internic. Write the static page to do a >> JAVA redirection into your network. The ISP will have the headaches of >> running the BGP and even if their link to you fails, chances are that >your >> static page that they are hosting will still be veiwable to the Internet. >> Simply write your JAVA redirector to have your secondary 3640's outside >IP >> address as a mirror site for immediate redirection. >> >> >> >> John Squeo >> Technical Specialist >> Papa John's Corporation >> (502) 261-4035 >-- >www.tasmail.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=20329&t=20329 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
