Introduction I had the issue where we had upgraded a system and as a result when I tried to SSH to another system which had not been upgraded I recieved the following error: Unable to negotiate with XX.XXX.XX.XX: no matching
Cisco Span Port Configuration
Introduction If you’ve ever needed to perform packet analysis for troubleshooting then you have options. If you have an IP base IOS image or above then it is likely you can do a packet capture directly on the switch however
Understanding top
Introduction If you ever have the need to understand the usage of the top command to show how loaded a *nix system is, then the best resource I have found is the following great post by Gary Newell. It contains
Useful Zabbix Operations
Introduction Some helpful Zabbix operations that always take me an age to find so putting here to make my life easier! Putting hosts into maintainence mode https://www.zabbix.com/documentation/2.4/manual/maintenance Restart zabbix agent service zabbix-agent restart
QLogic 12000 CLI Reference Guide
Introduction Just a big long list of CLI commands for easy reference. Note to use ? after the command to get a list of possible options.
Troubleshooting Juniper Netscreen VPNs Down
Introduction If you’ve ever needed to investigate a site to site tunnel which is down at 05:00 in the morning, this might just help you get to the bottom of it a bit faster. Steps to take Access your firewall
IOS DHCP Server – Database
Introduction If you require a Cisco device to act as a DHCP server. Do ensure you either set a database URL or the no ip dhcp conflict logging option otherwise the server can fail leaving your users free to complain
Install and Configure a TFTP Service on CentOS
Introduction If you are in need of a TFTP for config backups then sometimes the “old school” ways of doing things are still useful. Bear in mind the TFTP protocol incorporates no encryption so be wary about using it across
How to mount LVM partitions from rescue mode (Fedora/CentOS/RedHat)
Introduction If you ever run in to a scenario where you have a VM which won’t boot. You will need to use an install disc to get into rescue mode. Solution Boot your rescue media. Scan for volume groups: #
Rancid Logins Fail After ASA Upgrade to 9.1(7)
Introduction You’ve performed a code upgrade on an ASA firewall and suddenly Rancid decides it won’t login. You’ll get the message: spawn ssh -c 3des -x -l <user> <device> no matching cipher found: client 3des-cbc server aes128-cbc,aes192-cbc,aes256-cbc,aes128-ctr Error: Couldn’t login: