Multiple connections to ONE ISP

Answered Question
Mar 7th, 2010
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I have two connections to one ISP (one is over Radio channel the other is on-ground) who provides me with pool of public IP addresses. On my border routers (3825) I have BGP which announces this pool of addresses via one or another router (depending which channel is available. On-ground  has higher priority.) On ASA I configured SLA:


route outside 0.0.0.0 0.0.0.0 x.x.x.3 1 track 1
route outside 0.0.0.0 0.0.0.0 x.x.x.4 250

sla monitor 10
type echo protocol ipIcmpEcho [on-ground default-gateway] interface outside
num-packets 3
timeout 1000
frequency 3
sla monitor schedule 10 life forever start-time now


I have tested the SLA by shutting down the primary (on-ground) Internet channel. Everything worked fine: the default gateway switched to the Radio channel and back when I turned the on-ground channel back on.


The problem is: After some time (5 - 10 hours) ASA looses the default gateway and all services behind ASA become unavailable. After I reaply the SLA configuration provided above everything work fine for the next 5 - 10 hours and then it looses the default-gateway again.


Question:

  1. Does SLA on ASA work correct if the next hop for both DG are in one subnet. Technically there should be no problem but In all examples I have seen, never have I met that situation (next hops were always on different subnets)?
  2. If not first. What could be the problem?
  3. Are there any better ways to provide switching between two Internet channels in my situation?


Any help is appreciated!

Attachment: 
Correct Answer by Federico Coto F... about 7 years 4 months ago

Hi,


Should not be any problem, but you can track an IP avaiable to that path (instead of tracking the default gateway).


For instance, let's say you create a route:


route outside 4.2.2.1 255.255.255.255 gateway1


You can track 4.2.2.1 via interface outside (since that specific IP is always going to be reachable via that interface).


Let me know if the problem persists.


Federico.

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Correct Answer
Federico Coto F... Sun, 03/07/2010 - 08:41
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Hi,


Should not be any problem, but you can track an IP avaiable to that path (instead of tracking the default gateway).


For instance, let's say you create a route:


route outside 4.2.2.1 255.255.255.255 gateway1


You can track 4.2.2.1 via interface outside (since that specific IP is always going to be reachable via that interface).


Let me know if the problem persists.


Federico.

CCOintIPS Mon, 03/08/2010 - 22:46
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Thanks for your suggestion! I`ll try applying this configuration on Friday evening and let you know wether it helps.

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