Posts Tagged ‘Networking’

Classful routing/networking is no valid into today’s CIDR (Classes Inter-Domain Routing) networks; however, it seems that people are still over using the classful terminology almost interchangeably. The concept of classes in network is obsolete and should no longer be used when referencing network subnets because classful routing has defined network ranges that make them classful and CIDR does not. Read the rest of this entry »


I get this a lot in my field “I cannot ping the server, it must be down or a network issue”; however, I can log in and telnet to the machine and even RDP/SSH into the machine. Why is this? Simple, the machine is not responding to ICMP ECHO REQUESTS which is default behavior for some systems. Windows 7 and Windows server 2008 DO NOT respond to ping by default because their internal firewalls are set to NOT respond to ICMP ECHO REQUESTS. Therefore, the machine could show as DOWN because it doesn’t respond to ping but the machine could actually be alive and on the network.

I personally recommend allowing your machines to respond to ping because there are no benefits to not allowing it other than confusion that could arise from the unexpected. Hiding a PING response doesn’t provide more security because a TCP SYN scan could prove that your machine is alive and well if there are listening ports, among other methods of host discovery.

To put it simple, DO NOT RELY ON PING as a method of testing connectivity only.


Core vs. Edge Routing Topology

There isn’t a lot of talk about this; however, there is a lot of training material that references this debate and makes recommendations for edge based routing. For those not familiar with the topic I am talking about “Campus LANs” and not ISP networks where you essentially have to push routing to the edge for some customers. In my article I am talking about Core vs Edge in the aspect of where we perform all of our routing in a “Campus LAN” Read the rest of this entry »


If you think that when HP purchased 3com they would have either made everything a single code release (can we say, Juniper) or at least provide interoperability documentation that is easier to find and easier to read? You’re dead wrong and you may end up like me and make an assumption that keeps you here longer than you would like to be trying to fix it. To spare you the agony of it all I will just jump right into it… Read the rest of this entry »


How often do we run into problems and have to contact a third party vendor to get the resolution only to spend a large amount of time getting someone (sometimes ourselves) to stop the blame game and start working together? This seems to happen all the time in the IT field and this is frustrating as all hell and we as IT professionals and engineers need to put our ego and pride aside and work on the problem to benefit our customer and I’ll share my thoughts on the various scenarios… Read the rest of this entry »


Why do we as a society, at least in my generation, see that once we’re off the clock we’re just done and over? I am no advocate for working 80 hour weeks for 40 hour pay all the time; however, that is the spirit that moves you along and jets your career if you know what you’re doing. This is a new behavior I have seen in the field of networking when it comes to non-emergency related situations like documentation and “cleaning up” things like cabling and labels. Why have we become such a “5 O’Clock time to leave” society? Read the rest of this entry »


There are numerous occasions where we would like to utilize a more “human” name to view our physical switchport and router port connections; however, I find that most people don’t maintain these names/descriptions in a proper manner. While this configuration has no bearing on the operation of the switch it will create confusion for those who have to read through the documentation. Read the rest of this entry »


Just though I would put this out there for the world to read…use new network cables! If the cable doesn’t have a locking clasp you’re begging to have someone just brush by and jiggle it loose and then you’re troubleshooting an issue that looks complex when in reality all you have to is plug in a cable! ALWAYS USE NEW CABLES


We see it all the time here in the IT field…people floating around aimlessly during a maintenance doing nothing while others seem to be working harder than others. Why is this? For the most part I don’t believe we should be blaming them directly; rather, I think we need to blame management for not delegating responsibilities properly and efficiently… Read the rest of this entry »