With icmp inspection turned off and " access-list inside permit ip any any " on the inside interface (access-group inside in interface inside) and "access-list outside permit icmp any any echo" on the outside interface (access-group outside in interface outside) will i be able to successfully ping an inside host from an outside host.
And with the same above configuration will i be able to ping an outside host from inside host or will i need to add " permit icmp any any echo-reply" on the outside interface in the inbound direction for the return echo-reply to pass through the firewall.
how will the above configuration be different if icmp inspection is turned on .
Then you dont need to do that as fixup or inspect commands basically open the path for the return traffic. That's their job. These commands come in effect when their is any traffic ''through'' the firewall.' Same is the case for active FTP. If ip inspect ftp is specified you dont have to put an ACE for ftp-data. Its not required then.
you will either need to specifically allow echo-replies, or all icmp traffic to ping from inside to outside.
you may even need to allow echo's on the inside acl. or disable that acl altogether since it's permitting ip any any, anyway.