Yet another question of multihoming. I know there have been lots of discussions on this, but no concrete answer.
My scenario is simple. I have a cisco 1800 router with one ISP connection now. Going to add another internet connection to this router.
On the LAN, i have users who need internet access. I also have a webserver which needs access from internet all the time.
I dont think ill have issues failing over outbound connection from LAN -> internet , with IP SLA and PAT overload with route-maps...
What I have issues with is the inbound connection to the webserver through both ISP's. there will be dynamic dns updates which will force traffic to ISP 2 if the ISP 1 IP is not reachable. But my issue is static NAT on the end router.. I would already have a static NAT for webserver pointing to ISP 1.. how will I add another NAT to ISP 2 , for me to accept traffic from outside to webserver thro ISP 2 ? I dont want to run BGP , or using any other device for multihoming. (note - i have an extra router which can be configured as backup, with the ISP 2 line, and doing static nat on that router ? )
You're correct, you should not have any problem with the outgoing traffic.
For the inbound access to the internal server you can use route-maps on the static NAT to differentiate the traffic, for example:
ip nat inside source static 18.104.22.168 22.214.171.124 route-map ISP-1
ip nat inside source static 126.96.36.199 188.8.131.52 route-map ISP-2
In this way the internal web server (184.108.40.206) will be NATed to 220.127.116.11 when communicating with the first ISP and to 18.104.22.168 when communicating to the second ISP.
The other option of having another router which does the static NAT is valid as well.