Cisco ASA – I Cannot Ping External Addresses? (Troubleshooting ICMP)
KB ID 0000914 Problem Considering we use ICMP to test connectivity, the fact that it is not a stateful protocol can be a major pain! Last week one of my colleagues rang me up and said, “Can you jump on this firewall, I’ve got no comms, and I cant ping external IP addresses. I can ping the internet from the firewall and I can ping internal IP addresses form the firewall”. Solution 1. Before we start, lets get the basics...
Cisco ASA – ‘Prove it’s Not The Firewall!’
KB ID 0001049 Problem Yeah, it’s funny because it’s true! The article title might not sound like the most professional approach, but when the ‘Well it’s not working now’ finger gets pointed at the ‘firewall guy/girl’, they need to ascertain two things; 1. Is the problem actually the firewall, if not then help the frustrated party track down the actual problem. 2. If your problem IS the...
Cisco ASA ASDM – Packet Tracer Wont Work
KB ID 0001051 Problem I don’t usually use the graphical packet tracer tool, but I did this week, and this happened; Following error(s) occurred- packet-tracer input inside {protocol} inline-tag -l {source} {source port} {target} {target port} xml %Invalid input detected at ‘^’ marker Solution Well from CLI it worked fine, so I’m guessing it’s a fault in the ASDM. An Internet/forum search threw up a load...
Cisco ASA (acl-drop) Flow is Denied by Configured Rule
KB ID 0001108 Problem Packet-tracer is a brilliant troubleshooting tool, but sometimes interpreting the output proves to be more difficult that actually fixing the problem. If your output fails at the access-list section this is the sort of thing you will see; Petes-ASA# packet-tracer input inside tcp 10.2.2.10 80 123.123.123.123 80 —-Output removed for the sake of brevity— Type: ACCESS-LIST Subtype: Result: DROP Config:...