Unanswered Question
Mar 25th, 2009


How can I make load sharing via 2 routers with GLBP.

I configured GLBP in 2 routers, but they function in redundancy (Active/Standbay), not in load sharing( I mean Active/Active).


I have this problem too.
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i.ennassiri Wed, 03/25/2009 - 13:48

thanks for your response.

let me explain the architecture that I want to implement.

My Lan is behind a PIX, I have 2 routers connected to 2 ISPs.

I configured GLBP in routers (I tried Round robin and weighted), and I added a default route in the PIX to the GLBP address.

I issue a tracert from many hosts in the LAN to Internet, the result is the same from all hosts.

Jon Marshall Wed, 03/25/2009 - 13:53

Ah well then it won't load-balance. The issue you have is that the routers always see the same mac-address which is the mac-address of your firewall. So this mac-address will always be sent to the same router.

The mac-addresses of the hosts in the LAN are irrelevant because the routers only see the firewall mac-address.


Jon Marshall Wed, 03/25/2009 - 14:49

The pix is not really designed to do load-balancing between 2 ISP's.

You can either

1) use a router on which you could implement PBR or have 2 default static routes


2) if you want to use the pix then look into using OSPF between the pix and the 2 routers.


i.ennassiri Wed, 03/25/2009 - 15:23

If I use 2 static routes in the PIX with the same metric, How it will manage the traffic?

Jon Marshall Wed, 03/25/2009 - 15:30

The pix is not designed to handle 2 default routes with the same metric and load balance between the two. For that you need a router.

Like i say OSPF may be the only solution for you.


i.ennassiri Wed, 03/25/2009 - 15:36

thanks for your assistance.

I will try to do it via OSPF, and I'll keep you in touch.


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