I've read a couple of discussion about ICMP connection, but would like to know what seems to be the issue about Teardown ICMP connection:
6 Feb 15 2018 11:32:05 302021 175.45.x.x 0 172.17.x.x 1 Teardown ICMP connection for faddr 175.45.116.36/0 gaddr 172.17.x.x/1 laddr 172.17.x.x/1
The scenario is that there is a GRE tunnel setup in Cisco ASA,
INSIDE IP (Local Subnet): 172.17.x.x
GRE Tunnel (Virtual IP): 175.45.x.x
The inside IPs should be able to reach the GRE tunnel.