Cisco Router security basics and ASA firewall rules

[pelesmk () gmail com]

What types of ACls if any or other security rules should be used on an edge router or internal router which stands in 
front of an ASA firewall. 

I over recently overheard a conversation where they didn't want any ACLs on the router and have all ACLs happening at 
the firewall. I have a problem with this thought because of ip spoofing, DoS attacks, etc that would target the router. 
Am I thinking correctly or is there a way to defend against this at the firewall? I understand some ACLs can be made at 
the firewall and implementing long ACLs on the router can cause adverse network speeds, but some of the most basic ACLs 
must be at the edge router.

Please fill me in as I'm fairly new to ACLs and firewall implementations.

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