I have two SPs on my network . From SP_A i am taking STM-1 and from SP_B its DS3. Now my company doesnt have Service Provider independent public addresses.
I want to use STM-1 from SP_A as the primary link in case if this goes down then only traffic should come via SP_B.
I have 10 webserver which are being accessed by external internet users.
What i am planning to do static NAT for all these 10 webserver to both the SP's public addresses.
i.e. LAN IPs SP_A SP_B
Server-1 10.0.0.1 X.X.X.1 Y.Y.Y.1
Server-2 10.0.0.2 X.X.X.2 Y.Y.Y.2
likewise for rest 8 servers.
Now i want preference via SP_A link to access these 10 server , do i have to do something on DNS servers ? if yes then DNS server of my company or DNS server of SPs ?