Best practice wise - should I let the router or the ASA handle NAT
(Overloading)?
In the most general of design best practices NAT is performed between an inside and outside network. NAT overloading is generally performed at the edge when there is limited public IP address space. You can learn more about NAT overloading, also known as Port Address Translation or PAT, in RFC 2663 (PAT is referred to as Network Address Port Translation (NAPT) in section 4.1.2).
In this particular scenario you can argue that you have two inside and outside networks and will need to perform some form of NAT on both the ASA (whether that is the NAT overloading you're using now, NAT exemption, static NAT, etc) and the Cisco Router.
I can ping the 172.16.2.2 interface but not 172.16.2.1 from a pc
connected to one of the layer 2 switches (proves intervlan routing is
working -- i have a 172.20.100.8 address on the PC). Why can't I ping
172.16.2.1 from a PC but I can from the Layer 3 Switch?
The ASA 172.16.2.2 is receiving the ICMP echo-request but does not have a route back to 172.20.100.0/27. The echo-reply is actually being forwarded to the Router 172.16.1.1 via the default route.
And most of all -- Why can't I get out to the Internet from the Layer 3 switch?
Currently your ASA and Cisco Router do not have routes to internal devices other than their connected routes.
Your ASA configuration:
route outside 0.0.0.0 0.0.0.0 172.16.1.1 1
This will provide a default route via the outside interface, but how will the ASA know how to reach subnets residing behind the Layer 3 Distribution Switch?
You'll need to add routes to the internal subnets via the inside interface using the Layer 3 Distribution Switch as the next-hop IP address.
ASA static routing example:
route inside 172.19.12.0 255.255.255.240 172.16.2.2
route inside 172.19.3.0 255.255.255.0 172.16.2.2
route inside 172.20.100.0 255.255.255.224 172.16.2.2
Further reading: ASA static routing
Your Cisco Router's configuration:
ip route 0.0.0.0 0.0.0.0 200.200.200.200
Additionally, how will your border router know how to reach subnets other than it's connected routes, and the catch all default route via the outside interface's next-hop address 200.200.200.200?
Router static routing example:
ip route 172.19.12.0 255.255.255.240 172.16.1.10
ip route 172.19.3.0 255.255.255.0 172.16.1.10
ip route 172.19.100.0 255.255.255.224 172.16.1.10
ip route 172.16.2.0 255.255.255.224 172.16.1.10
Further reading: ISR static routing
I cannot get an ip address right now from the DHCP server (Windows).
Any insight into why?
Ensure you have end-to-end IP reachability between the client(s) sending DHCP discover messages and the DHCP server.
From what I can gather from your topology and configuration, the subnets 172.19.3.0/24, 172.19.12.0/28 and 172.20.100.0/27 should have no issues connecting to each other (assuming they are configured to use their respective default gateways) from a networking perspective.
You can remove the ip helper-address syntax from the SVI 100 given that the DHCP server is on the same segment and that command is used for a DHCP server(s) that is on a different segment.
interface Vlan100
ip address 172.20.100.1 255.255.255.224
ip helper-address 172.20.100.27
If nothing is before the date, it means that your router clock was set manually or is in sync with a NTP server by the time of the log.
If with an asterisk, it means you didn't set the clock or it isn't synced with a NTP server.
If there's a period, it means the clock was in sync but the NTP server is not accessible.
Source
Best Answer
The notion that "thou shalt not use ssh / telnet / SNMP to fix this problem" is broken. Use what you can to fix it. Yes, console logging at a lower baud rate relative to a faster stream of incoming console syslog messages is a pain; however you can't change what's already happened.
If nobody set up SNMP / telnet / ssh authentication methods and you can't change the environment which is generating so many logs, the right answer to take to your management is: "Sorry but this service was not set up in a maintainable manner. We have to take an outage to fix it."
Then fix what you know is wrong:
no logging console. I useno logging console guaranteed, but that's a personal preference.Our community is here to help if you have questions about how to improve failover performance, or configuring the items above.