(Cross posted from Super User per suggestion there)
At the office, I have inherited a network that I am still trying to fully comprehend. I have a problem today with a new connection between:
- A port on a Cisco Catalyst 3750 [WS-C3750G-48TS-S running C3750-IPSERVICESK9-M version 12.2(53)SE1]
- A port on a Cisco ASA 5505 [ASA Software version 8.3(2)]
The 3750 is home to a Vlan that has a few ports assigned to it.
interface Vlan3 description Internal network (172.18.160.0/24) ip address 172.18.160.1 255.255.255.0
I have a host (outside of my control) that needs to be in this VLAN (i.e it must have an address 172.18.160.something/24) that also needs to access the Internet.
To accomplish this, I ran a link from the Catalyst (Gi1/0/13) to the ASA (Ethernet 0/5). I configured the Catalyst port like so:
interface GigabitEthernet1/0/13 description To ASA, 172.18.160.69 switchport access vlan 3 switchport mode access speed 100 duplex full
I configured the ASA like so:
interface Vlan1 nameif inside security-level 100 ip address 172.18.160.69 255.255.255.0 interface Ethernet0/5 speed 100 duplex full
Then I plugged the host into Ethernet 0/4 on the ASA and instructed its owner to make its default gateway 172.18.160.69. I made a NAT rule in the ASA and set up some rules, and it's able to access the Internet without issue.
However, I noticed that the Catalyst reports a ton of packets being dropped toward the ASA.
Catalyst3750#show interfaces GigabitEthernet 1/0/13 | include counters|drops Last clearing of "show interface" counters 00:28:13 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 136909347
This is a huge number of drops, since there's not much traffic on this VLAN at all.
I tried these things:
- Make sure speed and duplex agree on both sides (100 Mbps / Full)
no cdp enableon the Catalyst Gi10/13
no keepaliveon the Catalyst Gi10/13
- Checked for excessive CPU usage on both
- Checked for excessive traffic on both
Am I missing something? Any help would be appreciated.