EIGRP router updation using HSRP

iqbal-zeeshan · ‎10-06-2009

Hi,

I would like to know that how can i stop EIGRP route updation in standby router until Primary router becomes active in HSRP scenerio. All uupdate to next hop should be from primary router.

Thanks in advance.

Giuseppe Larosa · ‎10-06-2009

Hello Zeeshan,

this normally doesn't create problems unless there are two different FWs in between.

The only thing you can do to build symmetrical paths is to make standby routes less attractive then those of primary router.

To do this on client vlan where HSRP is running you can use

delay 10000

increasing delay is the correct way to make this route worse then that advertised by primary router.

it is enough to increase delay over the value you see in

sh int type x/y on standby router

b)

if no FWs are involved you shouldn't have any issue if return traffic comes back to current standby HSRP router.

devices on the core can do load balancing towards the client vlan/ IP subnet if they see two equal cost paths.

Hope to help

Giuseppe

iqbal-zeeshan · ‎10-07-2009

Hi Giuseppe,

Thanks for your reply, you are absolutely right. Both primary/standby routers are connected with firewalls on failover scenario. Firewalls always getting EIGRP routes updates from Secondary router that's why reverse path of traffic becomes wrong. Due to firewall behavior it doesn't allow traffic when forward and reverse path not matches, because of that firewall suddenly stop passing traffic and may considering it as attack or threat.

Should I change the delay of EIGRP in standby router to stop broadcasting routes updating until the primary becomes active?

Thanks in advance.

Giuseppe Larosa · ‎10-07-2009

Hello Zeeshan,

>> Should I change the delay of EIGRP in standby router to stop broadcasting routes updating until the primary becomes active?

you cannot stop the updates coming from the standby router, the use of delay is a way to make its routes less desirable = higher metric not to delay their sending.

This is enough to ensure symmetric paths:

users use the HSRP active for inside to outside direction.

So R1 - FW1

Being the routes from primary HSRP preferred return path will be via FW1 -R1 ensuring flows are seen in both directions by FW1.

You need to increase delay with delay command on client side interface of HSRP standby router.

Hope to help

Giuseppe

iqbal-zeeshan · ‎10-07-2009

Hi Giuseppe,

Thanks for reply, my objective is not to stop the route update its just to proper the routes in all directly connected devices. I will increase the delay of firewall connected interface of standby router and moniter this.

Regards