Often times you may find that you need to block web messengers due to corporate security policies. Conventional ACLs work for messenger clients that communicate using specific ports, however, you may find some instant messengers run via a web browser…
Problem: Often times when you need console access to a Cisco device and you maybe too far away or due to various reasons you cannot console to/from a server with a serial port. Solution: Fear not! Providing you have a…
On Cisco IOS, ACLs can be applied in many different types of interfaces. The most commonly used is a Layer 3 interface. This includes physical, logical, or VLAN SVI interfaces that you can assign an IP to. ACLs can be…
The type of cable table Back to the fundamentals. Here’s a quick reference of what type of cable to use in what situation. Most modern networking equipment nowadays have auto MDI/MDIX which automatically detects and switches to cross-over or straight…
The Cisco ASA 8.3 is quite a major release despite the minor version number update. One of the major feature overhaul is the NAT. NAT and statics are no longer bound to an interface. It has moved towards an network…
Cisco portable product sheets are documents containing Cisco’s summary of various product comparisons and performance specifications. This includes a comparison of all Cisco’s switches switching performance, router routing performance, device VPN and encryption performance numbers, memory guildlines and more. This…
Today I ran into a problem where I wanted to find out what Linux process (PID) was listening on which port. You might A fellow sysadmin coworker showed me this command: lsof -i :port Lsof will list the PID and…
Cisco ASA license gone!? Today I experienced a failure during an upgrade of an ASA5505 which resulted in my Cisco ASA license disappearing. The ASA complained about error writing to flash. %Error opening disk0:/.private/startup-config (Read-only file system) Error executing command…
TFTP Server is often used by Cisco devices to manage their file transfers. Here is a quick guide on how to setup a TFTP server on Centos/Redhat. First obtain the RPM. In Centos, use yum to search and install tftp-server….
A regular Windows Server 2003 comes with two remote access sessions. This means you can open a maximum of two simultaneous Remote Desktop Sessions at one time, unless you install more terminal services licenses. However one thing you may not…