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New Member

BGP and 2 ISP. Default gateway problem :(

Hi, i have big trouble, maybe sombody knows how i can solve it.

Look, i have network like in attachement. I have full view and default gateway from ISP 1 by BGP, then for R1 and R2 def. gw is ISP1 IP. For R3 and R4 is similar situation but from ISP 2. In case if link 1 goes down then default gateway must be from ISP 2. But my problem in following:

when link 1 goes down, i still receieve default gateway from ISP 1 becouse BGP  session doesn't go down. I tried to solve the problem in that way: i created ip sla track and attache it to static route( My ip sla test ping R0 IP address and if it goes down then  traffic will go through  ISP 2, but i think that it is not the right way, becouse R2 still recieve default gateway from ISP1. How i can solve it without ip sla?

Everyone's tags (4)

Re: BGP and 2 ISP. Default gateway problem :(

change your bgp timers from the default say hello 3 dead 6 to isp1 and isp2, the lowest negotiated timers win.


New Member

Re: BGP and 2 ISP. Default gateway problem :(

I think u don't understand me. Link beween R1 and ISP 1 is available and BGP session is OK, but internet doesn't work, becouse ISP 1 has some poblems with there network and i want to forward trafiic through ISP 2 if i can't reach R0 IP through ISP1

Re: BGP and 2 ISP. Default gateway problem :(

Well not to sound rude - but welcome to the internet.  Everybody who runs routers with BGP and peers with providers faces the same issue.  As your router is receving a valid route from the ISP, why would'nt it use it ?? - that's the whole point.

There is no right or wrong solution to this - if IP SLA works for you, crack on.  On the other hand if it happended to me I would be picking up the phone and giving my ISP a peice of my mind, along with a request to get some of my circuit rental money back. But loops and blackhole routing occur in the internet - it's just one of those things I am afraid.


Re: BGP and 2 ISP. Default gateway problem :(

another option is to get your isp to send you the whole Internet routing table instead of just a default route.

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