Network tool to test network bandwidth and performance
install netperf by souce code on both server and client.

server side:
start netperf
#netserver

client side:
netperf -H remote.lalife.net

To open a new screen
#screen

To detach it
#screen -d

To get list of screens
#screen -list
13827.pts-4.servername

To resume it
#screen -r 13827

To sudo to a different user aaa then use screen
sudo -u aaa -s
script /dev/null
screen

Ref. http://dbadump.blogspot.com/2009/04/start-screen-after-sudo-su-to-another.html

start screen
#screen

detach
#screen -d

resume
#screen -r (single)
or
#screen -x (multi)

HELO smtp.lalife.net
MAIL FROM: test@localhost
RCPT TO: test@lalife.net
DATA
FROM:test@localhost
Subject: test smtp
test smtp.
.
QUIT

Another way to send mail by command line
echo “testmail” | mail -s “test” yan@yan.lalife.net

iptraf is a tool used to monitor the network traffic

To add more ports (beyond 104)
iptraf > Enter > Configure > Additional Ports

To change log interval
iptraf > Enter > Timers > Logging interval

Add/Delete/Active/Unactive Filter
iptraf > Enter > IP

Monitor traffic statistics by port
iptraf > Enter > Statistical breakdowns…

To run iptraf background for 10 min and send data to log files
/usr/bin/iptraf -B -s eth0 -t 10

Log file is under /var/log/iptraf/ by default