Question : Problem: Cisco 3750 and 3560 inter-vlan routing issue with ASA

Hi Cisco experts,

I need help with a cisco config that i can't figure out for the life of me.

I have 2x Cisco switches, 1x 3750 and 1x 3560 with IP Base images.

here is my current config:

both switches have "ip routing" enabled

3560 Switch (VTP Server):
VLAN 10 = 10.68.44.0/24
VLAN 10 IP = 10.68.44.1
VLAN 20 IP = 192.168.2.1
Fa0/48 = configured as no switchport with IP address 10.68.32.2  ==Connected to ASA 5505==> @ 10.68.32.1
Fa0/47 = Trunk port connected to 3750 on Fa1/0/47

3750 Switch (VTP Client)
VLAN 20 = 192.168.2.0/24
VLAN 20 IP = 192.168.2.2
VLAN 10 IP = 10.68.44.2
Fa0/47 = Trunk port connected to 3650

Connection between VLAN is working fine.  On VLAN 10, I can get out to the internet no problem...however, on VLAN 20 on the 3750, I can't get out.  I've added default-gateway and pointed it to 192.168.2.1...With no luck.

so, on VLAN20 on the 3750, how should i get routed out to the internet?




Answer : Problem: Cisco 3750 and 3560 inter-vlan routing issue with ASA

I would say, your previous static route to a particular host was incorrect.

here is cisco explanation:
Adding a static route to an Ethernet or other broadcast interface (for example, ip route 0.0.0.0 0.0.0.0 Ethernet 1/2) will cause the route to be inserted into the routing table only when the interface is up. This configuration is not generally recommended. When the next hop of a static route points to an interface, the router considers each of the hosts within the range of the route to be directly connected through that interface, and therefore it will send Address Resolution Protocol (ARP) requests to any destination addresses that route through the static route.

The practical implication of configuring the ip route 0.0.0.0 0.0.0.0 ethernet 1/2 command is that the router will consider all of the destinations that the router does not know how to reach through some other route as directly connected to Ethernet interface 1/2. So the router will send an ARP request for each host for which it receives packets on this network segment. This configuration can cause high processor utilization and a large ARP cache (along with memory allocation failures). Configuring a default route or other static route that directs the router to forward packets for a large range of destinations to a connected broadcast network segment can cause your router to reload.

Specifying a numerical next hop that is on a directly connected interface will prevent the router from using proxy ARP. However, if the interface with the next hop goes down and the numerical next hop can be reached through a recursive route, you may specify both the next hop and interface (for example, ip route 0.0.0.0 0.0.0.0 ethernet 1/2 10.1.2.3) with a static route to prevent routes from passing through an unintended interface.
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