Posts with the tag network speed
iperf can help you test the bandwidth of your network setup via a TCP connection:
# On one computer: iperf -s -w 2M -i 1 -p 2222 # On the other computer: iperf -c the.one.computer.local -w 2M -i 1 -p 2222
Or test via UDP (be careful,...
sudo aptitude install openvpn # open port 1194 (as shown here for the ufw firewall interface): sudo ufw allow 1194
Become an Certificate Authority
sudo mkdir /etc/openvpn/easy-rsa/ sudo cp -R /usr/share/doc/openvpn/examples/easy-rsa/2.0/* /etc/openvpn/easy-rsa/ sudo chown -R $USER /etc/openvpn/easy-rsa/ cat << EOF...
Let's say you network is kinda slow and you are sure that there is nothing wrong with your hardware (broken cables, bad switches etc.). The first thing you should have a look at are your DNS servers. If the primary one is unreachable and the secondary is, you network works...
If your ssh connection is established only with a delay of about 2-4 seconds (even when you are connected to a fast network), you can try the tips in this post.
What to try first
Debug you ssh connection: using
ssh email@example.com -p 28 -vvv (note the -vvv switch at the end).
Commonly used tools to monitor or test network bandwith are:
I really like
bmon for monitoring; it's a light-weight real-time CLI bandwidth monitor.
Its status output is given for the individual network interfaces on your computer.
sudo aptitude install bmon sudo bmon
Press g for console graphics and d for detailed stats.
Analyse the situation by taking a look at the configuration and stats:
ifconfig -a netstat -s
Check if your gateway and DNS servers are reachable. If only one of the dns servers is not reachable edit /etc/resolv.conf manually (will be overwritten by next network change).
To set the network interface eth1 to 100MBits...
listen on machine A:
nc -v -v -l -n -p 2222 >/dev/null
on newer versions of netcat (Ubuntu 10.04) you must use
nc.traditional -v -v -l -n -p 2222 >/dev/null
Send from machine B:
time yes|nc -v -v -n tklaus.selfip.org 2222 >/dev/null