Tuesday, May 21, 2013

How to see a Pre Shared Key for Site to Site VPN on Cisco ASA

To see the pre shared key for any Sites to Site VPN simply type the following in CLI:

more system:running-config | begin tunnel-group

This will change:

tunnel-group type ipsec-l2l
tunnel-group ipsec-attributes
pre-shared-key *****


tunnel-group type ipsec-l2l
tunnel-group ipsec-attributes
pre-shared-key fgaJcXri3zVq

More information about seeing the pre shared key on 6.3 here:

How to Make PPTP Connections Work Through a Cisco ASA

The most common reason  I find that PPTP connections do not work is because the inspect for PPTP it not enabled.

This is how you enable the inspect in the default inspection class:

conf t

policy-map global_policy
 class inspection_default
  inspect pptp
wr mem

This is needed whenever PAT is being used.

More details here:

How to Capture ARP Requests on a Cisco ASA

Many times I have had to prove that the firewall was not receiving any ARP replies from the workstation / router / switch / or server here is how I did it:

Log into the CLI and create a capture looking for only ARP request:

capture [CAP_NAME] interface [INT_NAME] ethernet-type arp

ASA# capure arpcap interface servers ethernet-type arp
ASA# show capture arpcap

//This is an example of a devices that is not responding to ARP:
   1: 20:26:41.822046 arp who-has tell
   2: 20:26:43.622508 arp who-has tell
   3: 20:26:44.622462 arp who-has tell
//We can see the firewall ( is requesting an ARP for but there is no reply

//This is an example of a devices that is responding to ARP requests:

   1: 20:30:59.077226 arp who-has tell
   2: 20:30:59.077562 arp reply is-at 0:45:00:07:a7:00

//We can see the firewall ( is requesting an ARP for and gets a reply that it has mac address 0:45:00:07:a7:00

You of course and also do a show arp to see the current arp table but the capture will prove the device is not arping or it will help you find if two or multiple devices are arping for the same IP address.

Cisco ASA Renaming Network Objects, Service Objects, Access Lists, and Details about Object-Groups

Renaming objects on the ASA is very simple:

NOTE: You cannot rename object-groups as of version 9.1 make sure you pick the correct name the first time!
Updating the objects names will automatically update the references in the policy.

Renaming Network Objects:
object network OLD_NAME rename NEW_NAME

Renaming Service Objects:
object service OLD_NAME rename NEW_NAME

Renaming Access Lists:
access-list OLD_NAME rename NEW_NAME

Tuesday, June 5, 2012

How to Download Packet Captures as a PCAP File to Use in Wireshark on a Cisco ASA

If you need to download your packet captures on a Cisco ASA/PIX so you can import them into Wireshark it is a very simple process.

I assume the following is true:
1. You have http (ASDM) access to the firewall
2. You already have a capture with captured packets: (See here how to create a capture)
If you want to just see the capture in the browser first to make sure there are packets you can do the following:

Command Format:

Once you know you have data in your capture you can download the pcap by doing the following:

Command Format:

How to Capture traffic on a Cisco ASA with No Config Changes

Problem: You need to capture traffic between and

In previous version of ASA/PIX code (7.2 and below) you had to go into config mode add a bi-directional access-list and then apply the packet capture. As of 7.2.1 you no longer have to do that and it makes creating captures a lot quicker and no configuration changes are made to the firewall since no access-list are created.

Command Format:
capture [CAP_NAME] interface [INT_NAME] match ip host x.x.x.x host x.x.x.x
capture jcap interface inside match ip host host

And while this rule looks like it would only capture traffic if sources from it is actually automatically bidirectional so will capture traffic if it sources from either address.

To see and manage your captures issue the following command:
show capture - This will list all fo the captures running on the ASA/PIX
show capture [CAP_NAME] - this will show the actually packets captured in the captures

clear capture [CAP_NAME] - this will clear the captures for one capture

no cap [CAP_NAME] - this will completely remove and stop the capture

There are many more options such as ports and protocols you can find those in the reference guide here:



Here are some more captures I regularly use:

Change the capture to gather whole subnets:
capture jcap interface inside match ip

If you need to see all the the traffic to and from one address you could make a capture like this:
capture jcap interface inside match ip host any

Capture ARP request and replies with the following:
capture arpcap interface inside ethernet-type arp

How to failover the standby ASA from the primary ASA

If for some reason you cant access the standby firewall but need you reload it and only have access to the primary firewall you can easily reboot the standby firewall by issuing the following command via cli:

failover reload-standby