Just got a /26 subnet from XO to use in tandem with our /27 subnet. I have a C2851 router sitting on the outside, then an ASA 5510 sitting internal and finally some C3750G switches. I am able to NAT internal IPs to the existing /27 subnet, but with the addition of the new /26 subnet, I am unable to resolve or route anything internal to any IPs in that subnet.
Am happy to post configs and Vision diagrams and/or maps. I have also checked with XO and they confirmed the new subnet is routeable for us.
Perhaps I am missing something on either the C2851 or the 5510?