Monitoring applications can be tricky. As a network engineer it's important that the applications that I serve up are available and working properly. To network engineers it's important that resources are up and running from the Internet. This script checks a variety of aspects pertaining to a public URL. Availability (TCP ports) Content matching (HTTP GET) … Continue reading Cloud-Based Web Application Check-Script
In some scenarios it is necessary to limit access to applications behind the F5. Lets say you are hosting an application that is load balanced and is publicly and privately accessible on the same virtual-server. This can be accomplished by using an iRule. In my scenario I need to limit access to applications running on an HTTP (non-SSL/TLS) … Continue reading iRule – IP Restrict Internal Applications
I know--that title is a mouthful, but it's actually pretty simple. A lot of environments out there have ACL's that have implicit permits because it was simply too much work to get a list of what needs to talk to what before the firewall(s) went into place. So, you've got an ACL applied to an … Continue reading ACL Debugging on ASA with ASDM
It used to be very hard for me to find these links online so I wanted to post them so you (and myself...) have a simple place to always find them. I use these for most of my generic diagrams. Logical and layout diagrams. All-purpose Cisco Visio Stencils These are good for physical layouts. You … Continue reading Looking for Cisco Visio Stencils?
Cisco devices are not commonly members of your domain. They are separate entities so it's important that they reference a source for time synchronization. This is especially important with logging. Cisco devices support the NTP standard for time synchronization. I set up an NTP server and point it to pool.ntp.org. I then and point my Cisco devices … Continue reading Configure Time on a Cisco Device
Every time that I design or discover a new network I create a logical VLAN diagram. It help others to gain an understanding of what's going on, discover problems and aid in discussion. Ninety-nine percent of the time I get asked for a network diagram over and over, even though I've sent it many times … Continue reading Logical VLAN Visio Diagram (Template)
If you aren't using Netflow on your internal network, you should be. It is a great way to troubleshoot chatty machines and the general flow of traffic on your network. It is also great to determine your backup windows. A lot of time admins just guess a time to kick off backups, but Netflow will … Continue reading Netflow on Cisco 6500