Why ICMP is blocked by ASA?
Short answer is because it is not in the list of state full inspection protocols.
You can see the default inspection protocols list on the capture.
So you will need to add ICMP to the default inspection policy in global policy which is under the service policies.
Doing it in CLI is simple;
policy-map global_policy
class inspection_default
inspect icmp
inspect icmp error
Make ASA Visible in Traceroutes
By default ASA is not visible in traceroutes as it does not decrement the TTL. To make it visible in a traceroute, we will need to add the following configuration to the default class in global policy.policy-map global_policy
class class-default
set connection decrement-ttl
There is another short command to do this,
ReplyDelete#Fixup protocol ICMP