Framed Routes, PAT, and ICMP

One of our customers receives their static /29 addresses in the form of a framed route from their ISP. Essentially the ISP sets the next hop for their range to the address assigned to their DSL link.

If traffic to this /29 is PATted though various internal hosts, there won’t be anything on the network which has those addresses assigned, and therefore nothing to respond to pings or other ICMP traffic.

The simplest solution is to create a Loopback interface on the router and assign it the /29 addresses:

interface Loopback100
 description -- STATIC IPS --
 ip address 150.101.x.x 255.255.255.255 secondary
 ip address 150.101.x.x 255.255.255.255
 ip address ....