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Load Balancing two ISPs without BGP

I am trying to redesign the infrastructure for my company (been here 3 months). I have to ISPs ATT (1.54) UUNET (1.54) which terminate into separate 2600's with WIC 1DSUT1. I will be installing a failover PIX configuration between the ISP routers and my internal network. (We have no firewall in place right now ;) I want to load balance outbound traffic between ISPs, I know I can do this with route-maps based on source address, but can I do this when the source address will be the external interface of the pix. We are not running BGP.

Would it be easier to load balance if I had both connections on one router? Instead of separate routers?

Any ideas on how to accomplish this would be greatly appreciated.

pjames@ourvacationstore.com

5 REPLIES
New Member

Re: Load Balancing two ISPs without BGP

Depending of your infrastructure and budget. If you have only 2 2600, you can load balance your outbound traffic by using multiple vlan in your internal network where the 2 routers used HSRP. Router A is active for subnet 1, Router B is active for subnet 2...etc.

If you can add a couple of routers, this couple can load balance all the traffic in failover setup (hsrp)...

Gold

Re: Load Balancing two ISPs without BGP

You could probably do this using static routes on the PIX, each covering some part of the IP address space, and each pointing to a different router towards a different ISP. For instance, on the PIX, you could configure four static routes:

0.0.0.0/0 to router 1

0.0.0.0/0 to router 2

0.0.0.0/1 to router 1

128.0.0.0/1 to router 2

This would split the ip address space in half, sending half to each router. The pix may not allow these short of prefix lenghts, so you may have to do more specifics, say /4's, or even a lot of /8's (I hope not, since that would be 256 static routes!), to split the address space up.

Russ.W

New Member

Re: Load Balancing two ISPs without BGP

Hi Russ,

How do the multiple static routes work? I have attempted to run dual default routes ie..

0.0.0.0 0.0.0.0 (outside) 1.1.1.1 (ISP A)

0.0.0.0 0.0.0.0 (DMZ) 2.2.2.2 200 (ISP B)

I tried it on a 3 port PIX515E with no success. Is there a way for the PIX to correctly use the route statements?, meaning if route A unavailable use route B with the larger metric.

I have been looking for a simply solution as above but thus far have had little luck.

Cheers,

Merlin

Gold

Re: Load Balancing two ISPs without BGP

According to the information on the PIX on CCO, it should be able to load share--but you'll have to make both paths have the same administrative distance. Right now, you're setting one with an administrative distance of 200, which means the route to ISP A will always be installed in the table, and the other route, to ISP B, will not be.

So, something like this:

0.0.0.0 0.0.0.0 1.1.1.1

0.0.0.0 0.0.0.0 2.2.2.2

It should work out seperate interfaces, I would think, as well.

:-)

Russ.W

New Member

Re: Load Balancing two ISPs without BGP

Inbound traffic you can load balance if sourced from outside. (IE. SMTP Traffic, WWW, FTP, etc.) Having 2 ISP's, and 2 separate IP Spaces, you can configure your DNS with 2 host entries on each service, Therefore DNS will round robin in-between the hosts, selectively sending inbound traffic via both ISP's.

Richard

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