Choices: What's the Top Net Operating System?
~ By Charlie Schluting
It's an eternal debate: Which operating system is the
very best ... the one for which we'd forsake all others?
We'll begin by examining how
effectively a network or systems administrator can operate using the
various tools available on several
Microsoft Windows, OS X,
Operating system usefulness should ultimately be determined
separately for each task: desktops for administrators, desktops for
servers. It doesn't make sense to talk about how Microsoft's IIS
makes a computer insecure when grandma will (hopefully) never be
using that feature. The journey beings with a few examples of tasks
that administrators do on a regular basis.
Sniffing the Wire
More often than they'd like, administrators need to
from the wire to examine various anomalies on their
This may seem like a straightforward task, but it really isn't. You
must have a network card that supports promiscuous mode, so the
hardware will read packets that aren't destined for it. Most
Ethernet cards support this mode, so in Linux, FreeBSD, and OS X
it normally "just works" when you run tcpdump. Sniffing wireless
packets isn't nearly as seamless. Many wireless cards, such as the
Airport, do not support this mode of operation. However, this isn't
an operating system issue, it's a hardware limitation.
Key Terms To
Understanding Net Operating Systems
The most important program that runs on a computer. Every
general-purpose computer must have an operating system to run other
A computer or device on
a network that manages network resources.
The underlying hardware or software for a system. For example, the
platform might be an Intel 80486 processor running DOS Version 6.0.
The platform could also be UNIX machines on an Ethernet network.
Sniffing packets in Windows, however,
requires third-party programs. There are numerous commercial packet sniffing
application for sale, but free ones exist too. Ethereal, a favorite among
many some Unix users, is available for Windows. It does require that a
Windows-based libpcap (called winpcap) library be installed first, but
operates very well once it's installed. In short, packet sniffing is a
common task, and can be done from any operating system.
Using Serial Ports
Talking to servers,
switches with your serial port is always an interesting experience. It can
seem that each
device has its own settings and requirements. Thus, the capability to
quickly change serial port settings, or define multiple profiles, is a
Shipped with Windows, HyperTerminal does the
job. Its terminal emulation isn't always the best, but most of the
complaints result from users not using the correct terminal type.
HyperTerminal provides a mechanism to create multiple saved profiles, so
dealing with various serial port settings isn't too cumbersome. Many people
dislike HyperTerminal, but you can get the job done using it.
Linux and FreeBSD the options are all the same. They all come with the "tip"
program, which uses /etc/remote to define profiles. It works well enough,
but new users generally prefer to install minicom, which builds on all Unix
operating systems and provides the same functionality.
OS X, however, presents some challenges. Most
hardware comes lacking a
so you need to purchase a serial-to-USB adapter. Some of these adapters come
with drivers for OS X, so the only remaining issue is finding an application
to talk to the serial port. Minicom can also be installed on OS X. It seems
that you can get the job done with any operating system, again.
Trunking for Peace
When operating a network with many
virtual LANs, the
operator might need to access a specific network directly. Instead of
plugging his or her laptop into a switch port configured to live on a
specific VLAN, he can instead run a trunk to his workstation. The VLAN trunk
is the method by which switches and routers connect together to share
networks. If you connect a trunk to a desktop machine, you can configure it
to talk directly to specific VLANs. This is very beneficial for
troubleshooting, and makes sniffing packets on all networks much easier.
The idea is that you'll need to create
multiple interfaces, one for each network you wish to talk to. Since this is
on a VLAN trunk, you also need to specify which VLAN tag is being used, so
it knows which packets to send to the new virtual interface. When configured
properly, an administrator can easily bring up an interface in any VLAN that
exists on the trunk. Beyond simply sniffing broadcast packets, this is very
useful when troubleshooting routing issues too.
802.1q (the trunking protocol) is supported
on a few select gigabit network cards from Sun. Before the latest patches,
VLANs were quite painful to get working on a SunFire V210 with Solaris 9.
It's supposed to work, but results vary.
In FreeBSD and OS X, creating a new VLAN
interface and assigning
is a snap. The required commands are built into the ifconfig utility. Linux
provides the vconfig utility that provides the same functionality. More
expensive network cards will handle VLAN tagging (i.e. adding the VLAN id,
within hardware). It can be difficult to tell whether the VLAN tags are dealt
with in hardware vs. the operating system's software in Linux and BSD. The
telltale method is to run tcpdump and see if the VLAN identifications are in
the packets. If not, then they are being stripped by the hardware before the
operating system gets the packet. This can be quite confusing at first, but
the ability to do this in software means that any network card can be used
to talk 802.1q.
Windows doesn't support 802.1q natively, but
some network cards' drivers do provide this functionality. The Intel Pro
cards come with a simple GUI for configuration of VLANs. It works, but
this is dependent on the network card and vendor's software.
These are just three examples of tasks that
many people perform daily. In a more general sense, most people will use SSH
or a remote desktop to manage a server, which can be done from any operating
system. There are likely numerous other examples of administrator utilities
that function only partially on the various platforms.
In general, the more advanced features are
going to show up in open source operating systems first. Others may show up
as feature-limited versions in commercial operating systems, or may not
appear at all. A given platform's usefulness to an administrator is mostly
going to depend on what the administered servers are running, and, of course,
that person's level of comfort with the operating system.
Did You Know...
In general, the more advanced features are going to show up in
open source operating systems first. Others may show up as
feature-limited versions in commercial operating systems, or may
not appear at all. ~ Enterprise Networking Planet,