Language Selection

English French German Italian Portuguese Spanish

Ping: ICMP vs. ARP

Filed under
HowTos

Network and system administrators are well-versed in using the ping utility for troubleshooting purposes, but where do you turn when ping doesn't do the trick?

Pinging a host is usually the first step in determining if the host is properly connected to the network. If the host does not respond to a ping request, the host is usually assumed to be offline.

But is it?

Today almost every organization employs firewalls for enhanced security. Firewalls can be set up in such a way that Internet Control Message Protocol (ICMP) requests are blocked, which means that traditional pings do not work. Setting a firewall to block ICMP requests is based on the theory that if a would-be hacker cannot "see" the target, he may not attack the host.

This makes system and network administration more difficult. A failed ping is no longer a valid test -- the user may have enabled a firewall that is blocking the ping, but the host may still be up. Before a network administrator can accurately determine if a host is down, the user needs to turn off all firewall applications -- or at least turn off any rules blocking ICMP -- which is probably asking too much of the average user.

ICMP vs. ARP.

More in Tux Machines

Leftovers: Software

today's howtos

Leftovers: Gaming

Mozilla Firefox 32 Officially Released

It's been a little over a month since the previous Firefox stable release and the developers have now pushed a new major update to users. This latest iteration of Firefox brings just a few major features for regular users, but it excels in other areas like better HTML 5 support. The official announcement for Mozilla Firefox 32 hasn't been made public just yet, but the mirrors now host the latest stable versions. It will take them a while to post anything official, and some time may go by until this new release hits the repositories, but you now can get to see what has changed. Read more