Help with NAT rule

I have a 1841 rounter, connect to two diff.. ISP, I set up sla, so if ISP "A" fail it fail to ISP "B". The problem I have is when ISP "A" is up I want to use my public IP that I got from ISP "B" in my NAT rule to get access inside my network, eg RDP, SMTP. The NAT rule only works when I fail over to ISP "B"
Can someone point out to me what I am missing.

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Comments

M4verick

Someone please correct me if I'm wrong as I haven't set this up myself before. But I would think you'd probably have to work with both ISPs regarding this issue.

I think you'd talk to ISP A to route for that IP address through BGP so that the rest of the internet knows that your IP address could be reached through ISP A as well as ISP B. I would also imagine there would probably be an additional fee required for that.

networker050184

M4verick is correct. The kind of redundancy you want usually needs a BGP set up and your own IP space.

ColbyG

networker050184 wrote: »

M4verick is correct. The kind of redundancy you want usually needs a BGP set up and your own IP space.

I'm not sure what the OP is saying exactly. If he wants to ALWAYS use the IP from ISP B, this is possible. But if he wants to failover automatically, yea, he'll need BGP.

If he always wants to use ISP B's IP, he can do that by load balancing instead of running failover. Something like this:

IOS NAT Load-Balancing with Optimized Edge Routing for Two Internet Connections - Cisco Systems

Then he uses the Static NAT statement with ISP B's IP. But he obviously loses connectivity if ISP B is down.

networker050184

ColbyNA wrote: »

I'm not sure what the OP is saying exactly. If he wants to ALWAYS use the IP from ISP B, this is possible. But if he wants to failover automatically, yea, he'll need BGP.

If he always wants to use ISP B's IP, he can do that by load balancing instead of running failover. Something like this:

IOS NAT Load-Balancing with Optimized Edge Routing for Two Internet Connections - Cisco Systems

Then he uses the Static NAT statement with ISP B's IP. But he obviously loses connectivity if ISP B is down.

Yeah, but if his link to ISP B goes down there will be no way to reach that IP through ISP A without getting ISP A to advertise ISP Bs IP space.

ColbyG

networker050184 wrote: »

Yeah, but if his link to ISP B goes down there will be no way to reach that IP through ISP A without getting ISP A to advertise ISP Bs IP space.

That's what I said in the last line.

networker050184

ColbyNA wrote: »

That's what I said in the last line.

I just skimmed. Your idea was so horrible I couldn't concentrate.

ColbyG

hahahahahahahaha

M4verick

networker050184 wrote: »

I just skimmed. Your idea was so horrible I couldn't concentrate.

hahahahaha

Thanks for confirming my theories though guys!

APA

networker050184 wrote: »

I just skimmed. Your idea was so horrible I couldn't concentrate.

BAHAHA! Classic