24-2
Cisco ASA Series Firewall CLI Configuration Guide
Chapter24 Troubleshooting Connections and Resources
Testing Your Configuration
Enabling ICMP Debugging Messages and Syslog Messages
Debugging messages and syslog messages can help you troubleshoot why your pings are not successful.
The ASA only shows ICMP debugging messages for pings to the ASA interfaces, and not for pings
through the ASA to other hosts.
To enable debugging and syslog messages, perform the following steps:
Examples
The following example shows a successful ping from an external host (209.165.201.2) to the ASA
outside interface (209.165.201.1):
ciscoasa(config)# debug icmp trace
Inbound ICMP echo reply (len 32 id 1 seq 256) 209.165.201.1 > 209.165.201.2
Outbound ICMP echo request (len 32 id 1 seq 512) 209.165.201.2 > 209.165.201.1
Inbound ICMP echo reply (len 32 id 1 seq 512) 209.165.201.1 > 209.165.201.2
Outbound ICMP echo request (len 32 id 1 seq 768) 209.165.201.2 > 209.165.201.1
Inbound ICMP echo reply (len 32 id 1 seq 768) 209.165.201.1 > 209.165.201.2
Outbound ICMP echo request (len 32 id 1 seq 1024) 209.165.201.2 > 209.165.201.1
Inbound ICMP echo reply (len 32 id 1 seq 1024) 209.165.201.1 > 209.165.201.2
The output shows the ICMP packet length (32 bytes), the ICMP packet identifier (1), and the ICMP
sequence number (the ICMP sequence number starts at 0, and is incremented each time that a request is
sent).
Command Purpose
Step1 debug icmp trace
Example:
hostname(config)# debug icmp trace
Shows ICMP packet information for pings to the ASA interfaces.
Step2 logging monitor debug
Example:
hostname(config)# logging monitor debug
Sets syslog messages to be sent to Telnet or SSH sessions.
Note You can alternately use the logging buffer debug
command to send log messages to a buffer, and then view
them later using the show logging command.
Step3 terminal monitor
Example:
hostname(config)# terminal monitor
Sends the syslog messages to a Telnet or SSHsession.
Step4 logging on
Example:
hostname(config)# logging on
Enables syslog message generation.