Posts Tagged ‘HP ASE’

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 »