Various ways to debug networking issues on an IBM i using the 5250 or SSH.

5250 Commands for debugging networking on the IBM i

QSYS/PING RMTSYS(example.com)
QSYS/TRACEROUTE RMTSYS(example.com)
QSYS/NETSTAT

or you could download Perzl binaries and run various AIX/Unix tools for networking.

PASE/AIX/IBM’s Unix tools for networking

NetCat
Downlaod: http://www.perzl.org/aix/index.php?n=main.netcat
Nmap 
Downlaod: http://www.perzl.org/aix/index.php?n=main.nmap
iperf 
Downlaod: http://www.perzl.org/aix/index.php?n=Main.iperf
Openssl (usually already installed)

openssl s_client -connect example.com:443

Example of downloading and installing a tool from perzl’s website

wget http://www.oss4aix.org/download/RPMS/netcat/netcat-1.10-2.aix5.1.ppc.rpm
rpm –ignoreos –ignorearch –nodeps –replacepkgs -hUv netcat-1.10-2.aix5.1.ppc.rpm

group system does not exist - using root
netcat                      ##################################################
Example of using netcat
Listen on a server socket :
$ netcat -l -p 45678
In a new terminal session connect to the local server socket from client
$ netcat 127.0.0.1 45678

Send a message to the server

$ netcat 127.0.0.1 45678 
Hello Server this is the client
On the server we should see :
$ netcat -l 45678
Hello Server this is the client

ctrl+c twice to break out of the connection

Bandwidth Test

Measure the actual network speed between your IBM i and your computer as network packets traverses various ethernet/wifi cards, wired/wireless connections, routers and switches.

#Server
iperf -s -i 1
#client
iperf -c <server_ip> -i 1
#other options
iperf –help

#Server (note sometimes nc is netcat instead)
nc -v -v -l -n -p 2222 >/dev/null
#Client
time yes|nc -v -v -n 192.168.0.8 2222 >/dev/null
#Stop by using ctrl+c
sent 87478392, rcvd 0
real 0m9.993s
#Take the bytes sent times by 8 (conversion bytes->bits) and divided by time elapsed to get Mb/s (Megabits per second)
#70Mb/s (=87478392*8/9.993)

reference: http://deice.daug.net/netcat_speed.html

 

OSI Networking Layers

Below is the OSI model which is the way communications between computer systems usually travel from a high level view without digging into the technologies used.
osi