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Cisco PIX and router question

Posted on 2007-03-26
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Last Modified: 2010-04-17
Is it possible to drop the inside link on the PIX if the outside link fails?
I wondering as i wish to have something similar to the diagram below... where their will be a secondary WAN link that will take over if the primary one goes down.
I need the router to know when the primary WAN link goes down, as i will have 2 default gateways set up with metrics favouring the primary route. when the line goes down the second default gateway will jump into place.

    WAN LINK 1 - - - - - - - - - outside(PIX)inside - - - - - - Router- - - - - - LAN 1
                                                                                             |
                                                                                             |
    WAN LINK 2 - - - - - - - - -  - - - - -- - - - - -outside(PIX)inside

Or

If anyone has a better idea of how to achieve what i want?
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Question by:chouckham
9 Comments
 
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by:jasonr0025
ID: 18797869
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2050400028%201138610150&name=2%20x%2010/100Mbps

Here are several load balancing routers ranging from cisco to linksys.   I assume you will want a cisco.  Using one of these will allow you to use one pix behind it.

Good luck
Thanks
Jason
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by:RPPreacher
ID: 18800107
Set up a dynamic routing protocol on both PIX and the interior router.  If the WAN link is down, the routing tables on the PIX will update.
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by:lrmoore
ID: 18800129
Assuming that the Router is the default gateway of LAN1, you will have to use SLA monitor and object tracking to change routes, since the inside interface of the PIX will not drop if the WAN link is down.
Reference and examples:
http://www.cisco.com/en/US/products/sw/iosswrel/ps5413/products_feature_guide09186a00801d862d.html
Just be sure to select the approriate objects to track. In your case it might be the upstream default gateway set on each PIX..
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by:lrmoore
ID: 18800182
I agree with RPPreacher to a point. In normal situations a dynamic routing protocol (PIX only supports RIP and OSPF) would be the answer. I assumed from your diagram that both of your WAN links are either DSL or Cable/broadband and hand you off an Ethernet feed. In this case, if the true WAN link is down, your WAN interface will not ever go down and will not trigger a routing update. The router (probably a modem in  your case) would also have to be participating in a dynamic routing protocol with the PIX on the WAN side.
With dual broadband connections with no intelligent router in front of the pix, you have to use something with more intelligence like the SLA MON.
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by:chouckham
ID: 18814971
The primary WAN link is going to be a dedicated 2 meg line.
Is there a way of detecting its down and not just detecting that the link to the ISP router is down?

The secondary WAN link is going to be an ADSL type connection.

The final set up is going to look more liek this...

WAN LINK 1 - - - - - - - - - outside(PIX)inside - - - - - - Router- - - - - - - - - LAN 1
                                                                                             |
                                                                                             |
WAN LINK 2 - - - - - - - - - outside(PIX)inside - - - - - - Router - - - - - - - -  LAN 2

All traffic will go out through WAN LINK 1 unless its down. it will then go out through WAN LINK 2.

Can anyone tell me how i can set this up so the routers know or get notified when the connections are down.

Thanks for any help :)

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by:lrmoore
ID: 18815698
SLA Monitor is your friend, and it is the most appropriate technology to solve your issue. It can determine not only if the actual WAN link is down, but if the telco loses their peering point and the link past the WAN link is down.

It looks like you have 2x PIX's also? Do you have 1 or 2 internal routers?

WAN LINK1 2Mb link will have to have an actual router, either yours or the telco's. It will be Ethernet between the WAN router and the PIX. If you own this router, and the PIX is not a 501, then you can use OSPF between the router and the PIX1, the use OSPF between the PIX inside and the inside router to redistribute default gateway.

WAN LINK2 ADSL will be delilvered with a modem and hand you off Ethernet. This router does not support OSPF or any other dynamic routing protocol. There is virtually no way that the PIX can determine if the WAN link is down because the Ethernet link will not drop. If the PIX can't know, then that information can't be passed to the internal router so that router will know which patch is best.
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by:chouckham
ID: 18815809
>It looks like you have 2x PIX's also? Do you have 1 or 2 internal routers?

yeah 2 PIX 506E's and 2 internal routers. set up like below. (ive also included the isp router)

(WAN LINK1) ISP Router - - - - - - - - - outside(PIX)inside - - - - - - Router- - - - - - - - - LAN 1
                                                                                                               |
                                                                                                               |
(WAN LINK 2)ADSL Router - - - - - -  - outside(PIX)inside - - - - - - Router - - - - - - - -  LAN 2

I want all traffic to go to WAN LINK 1 - if it fails i want the traffic to go to WAN LINK 2

(not bothered if WAN LINK 2 fails - by that point we should have the primary wan link back up)

How will i set all this up then?
On each internal routers i was just gonna use 2 default gateways with metric's favouring WAN LINK 1
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lrmoore earned 500 total points
ID: 18815946
Are you using HSRP inside the routers? How will the LAN know which router to use?
HSRP normally tracks interface events to provide failover, but that won't happen in your case.
You need something more dynamic than plain static routes.
Have you looked at the document in the link I posted above? It has several examples and explains the feature very well, and it is not that complicated.

This is somehting like what I would envision for your internal router(s)
R1:

interface FastEthernet 0/0
 description LAN
 ip address 10.1.1.2 255.255.255.0
 standby 1 ip 10.1.1.1
 standby 1 preempt
 standby 1 priority 100

interface FastEthernet 0/1
 description uplink to FW
 ip address 10.2.2.3 255.255.255.0

ip sla monitor 1
 type echo protocol ipIcmpEcho 1.1.1.1  <== some public IP owned by telco
 timeout 1000
 frequency 3
 threshold 2
ip sla monitor schedule 1 life forever start-time now
track 123 rtr 1 reachability
access list 101 permit icmp any host 1.1.1.1 echo
route map MY-LOCAL-POLICY permit 10
 match ip address 101
 set interface FastEthernet 0/1 null 0
!
ip local policy route-map MY-LOCAL-POLICY
ip route 0.0.0.0 0.0.0.0 10.2.2.1 track 123
ip route 0.0.0.0 0.0.0.0 10.2.2.2 254

R2:

interface FastEthernet 0/0
 description LAN
 ip address 10.1.1.3 255.255.255.0
 standby 1 ip 10.1.1.1
 standby 1 preempt
 standby 1 priority 110

interface FastEthernet 0/1
 description uplink to FW
 ip address 10.2.2.4 255.255.255.0

ip sla monitor 1
 type echo protocol ipIcmpEcho 2.2.2.2  <== some public IP owned by telco
 timeout 1000
 frequency 3
 threshold 2
ip sla monitor schedule 1 life forever start-time now
track 123 rtr 1 reachability
access list 101 permit icmp any host 2.2.2.2 echo
route map MY-LOCAL-POLICY permit 10
 match ip address 101
 set interface FastEthernet 0/1 null 0
!
ip local policy route-map MY-LOCAL-POLICY
ip route 0.0.0.0 0.0.0.0 10.2.2.2 track 123   <== reverse of R1
ip route 0.0.0.0 0.0.0.0 10.2.2.1 254          

NOTE: you can use MHSRP to pseudo load-balance if you want.
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Author Comment

by:chouckham
ID: 18823208
Thats great ill try it out thanks
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