ASA Firewall

[SathishkumarSaravanan0348]

Hi All,

Please find the output of the interface in firewall:

FW# sh ip
System IP Addresses:
Interface Name IP address Subnet mask Method
GigabitEthernet0/0 outside 10.238.3.105 255.255.255.252 CONFIG
GigabitEthernet0/1 inside X.X.X.X 255.255.255.248 CONFIG
Management0/0 management X.X.X.X 255.255.255.0 CONFIG

In the above I need to know which device the outside interface is connected. I found that the inside is connected to the core  switch. 

Thanks.

[Seb Rupik]

Hi there,

The command sh arp , will display the ARP cache of the ASA sorted by interface. The outside interface is a /30 so I would expect to see only one other dynamic address. This will be your gateway. Take note of the MAC address.

It sounds like your ASA outside is connected to a switch so the Layer 2 connection is obvious but the Layer3 endpoint needs to be discovered. On the upstream switches issue the command:

sh mac-address | inc <MAC_ADDRESS_FROM_ASA_ARP_CACHE>

...this will show which interface the MAC address has been learnt on. Keeping hopping through your network using this command and you'll eventually find the gateway.

cheers,

Seb.