access-list 105 deny icmp any any echo
access-list 105 permit ip any any
int fa 0/0
ip access-group 105 in
Now in my lab manual they created this list for R2. Why? they have clearly used Extended ACL and as far as I know, Extended ACL is used on source, so isn't our source the PCs? In the next part we are required to permit one host for the FTP access and again the router used for extended ACL is R2. Why is that so?