This may have a ridiculous answer but I have been working on it for a while
so I am asking for help :)  I got asked why the following
scenario isn't working and I am failing to figure out why:


R1 -> default gateway is R2
R2 statically routes all RFC1918 addresses to Loopback100
Loopback100 should be able to use an ACL to permit or deny ICMP and log

If I do this scenario from the ingress physical port on R2 everything works
great.  When repeated with lo100 it fails:

CONFIG:

R1
conf t
int f0/0
ip address 192.168.1.1 255.255.255.0
no shut
exit

ip route 0.0.0.0 0.0.0.0 192.168.1.2


R2
ip route 10.0.0.0 255.0.0.0 lo100
ip route 172.16.0.0 255.240.0.0 lo100
ip route 192.168.0.0 255.255.0.0 lo100


ip access-list extended blackhole
 permit icmp any any log
 deny icmp any any log

int lo100
ip address 10.100.100.100 255.255.255.255
ip access-group blackhole in
no shut


TEST:
R1#ping 10.100.100.100

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.100.100.100, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms


DEBUG FROM R2:
Jun 12 16:43:21.943: ICMP: echo reply sent, src 10.100.100.100, dst
192.168.1.1
Jun 12 16:43:21.955: ICMP: echo reply sent, src 10.100.100.100, dst
192.168.1.1
Jun 12 16:43:21.959: ICMP: echo reply sent, src 10.100.100.100, dst
192.168.1.1
Jun 12 16:43:21.963: ICMP: echo reply sent, src 10.100.100.100, dst
192.168.1.1
Jun 12 16:43:21.967: ICMP: echo reply sent, src 10.100.100.100, dst
192.168.1.1

NO HITS ON ACL
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