Nexus – Interface Error disabled. Reason: DCX-No ACK in 100 PDUs / Cisco Bug ID CSCtq30118
This is the first time I encounter this error on the disabled interface so lets dig in! N5K2# sh int statusEth100/1/31 Node3 dcxNoACKi trunk full...
How to upload troubleshoot file from FXOS (Firepower eXtensible Operating System ) over CLI – Cisco Firepower 2100/4100
Cisco many times will request “troubleshoot file” when working with Firepower 2100/4100 chassis. It is because FXOS is the underlay OS either you run ASA...
Cisco AnyConnect Secure Mobility Client Arbitrary Code Execution Vulnerability – cisco-sa-anyconnect-ipc-KfQO9QhK
This bug is not as clear as you would typically see. In the Cisco Advisory for cisco-sa-anyconnect-ipc-KfQO9QhK / CVE-2020-3556 they partially talk about the local...
How to adjust Cisco ASA capture buffer to allow higher tcp dump size
When troubleshooting communication across the network a lot of times you will be required to provide artifacts on why and who causing the RESET(RST) or...
Error opening nvram:/startup-config (Read-only file system) – Cisco ASA
Recently, I have encountered an issue where my virtual ASA couldn’t write memory (copy running-configuration startup-configuration). asav/pri/act(config)# wrBuilding configuration...Cryptochecksum: b3d790bf 1f8ae83c b72965aa 295bb863%Error opening nvram:/startup-config...
UCS Service Profile – Cannot derive mac address or wwpn from virtualized port
When associating physical server to the service profile you may get stuck at “cannot derive mac address from virtualized port“ making server to be in...
How to allow traceroute on Cisco ASA – udp 32 Drop-reason: (ttl-exceeded) ttl exceeded
When you are in need to allow traceroute for whatever reasons (which is blocked by default) you’ll see a lot of references to modify global...
How to copy image to standby firewall (Cisco ASA)?
If you are like me and think that there should be a way to copy files from primary unit dir via failover/ha link well you’ll...
Cisco ASA Firepower – TFTP %ERROR: Signature not valid for file disk0:/cisco-asa-fp2k.9.x.x.x.SPA
Short and simple. If you are running Firepower 2100 or 4100 on ASA image either stand alone or context mode you have to install new...
Key exchange failed. No compatible key-exchange method. The server supports these methods: diffie-hellman-group14-sha256 – Cisco ASA
If you are trying to ssh but you are getting this message (or similar) shown below its probably your client software. No compatible key-exchange method....