Introduction The deployment of dual WAN firewall solutions in branch offices is often required to ensure fail-over for unreliable WAN connections. This type of deployment however can add additional complexity compared to a full BGP setup using capable routers. With
DNS Based Challenge Verification SSL Certificates
Introduction Letsencrypt offer free SSL certs but the one caveat is they have a short 90 day expiry. There is the option to setup automatic renewal using file based verification if the web server is accessible publicly, however if you need
Linux Bash Printing Columns using AWK
Introduction If you ever had a requirement to parse huge firewall logs looking for something specific then trust me you will likely need to use awk possibly in combination with other commands such as grep, sort and uniq. Solution Get
VMware ESXi 5.5 – Hardware Health Status shows “Unknown”
Introduction If you ever find that the sensors on your ESXi server show an Unknown status. You may think a reboot is your only option to get it functioning again however not true. Solution If you SSH to the system
Saving a read-only file edited in vi / vim
Introduction A simple but annoying one. You open a configuration file with no intent to change anything, then you think I’ll just change that .. and this.. and 20 minutes later when you go to save you realise you opened
Juniper Netscreen Track IP
Introduction IP tracking can be used to change routing based on the connectivity of configured IP addresses. This can be used with either default routes or static routes which in normal circumstances would not change in the event of reachability
Unable to SSH Between Systems
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