We are currently planning out a site redundancy for the company, and customers vpn to a single ip address. The second site is at a separate geographical location. ISP1 is the same between the two sites and ISP2 is the second connection at site 1 and ISP3 is the second at site 2.
Currently we have a full /24 public address. Can I subnet the /24 into 3 parts and take one of the parts and advertise the same address from the same AS# from two different locations.
Current x.x.x.255 /24
Want to advertise:
x.x.x.0/224 from both site 1 and site 2
x.x.x.32/224 from site 1
x.x.x.64/224 from site 2
Yes, you can.
You need to make sure those subnets are part of the routing table while they are being advertised into BGP.
You could do so by using static routes to null0.