If you want to test the speed of your Internet connection, you just load up the SpeakEasy SpeedTest.

But what if you want to test the speed of your internal network? Use iPerf. You need two linux machines (fedora in this case) and a minute or two of quiet network (ideally).

On both machines run:

yum -y install iperf

to get the package. Now on the server, run:

iperf -f m -i 10 -u -N -s -p 11111

if your iptables firewall is in the way, add a rule or just stop it for now:

/sbin/service iptables stop

and on the client, run:

iperf -f m -p 11111 -u -c SERVERNAME -t 60 -b 100M

for a hundred megabit network. You should see output like:

Client connecting to SERVERNAME, UDP port 11111
Sending 1470 byte datagrams
UDP buffer size: 0.10 MByte (default)
------------------------------------------------------------
[  3] local 192.168.1.2 port 33833 connected with 192.168.1.3 port 11111
[  3]  0.0-60.0 sec    685 MBytes  95.7 Mbits/sec
[  3] Sent 488301 datagrams
[  3] Server Report:
[  3]  0.0-60.0 sec    685 MBytes  95.7 Mbits/sec  0.065 ms    0/488300 (0%)
[  3]  0.0-60.0 sec  1 datagrams received out-of-order

Hey, cool, this Cisco 3500XL with two linux servers can push 95.7Mbps.