In general, for each command <command> in linux shell one can use:
"man <command>" and "info <command>" to get manuals / usage instructions
"command --help" to get short usage instructions
"info command" to get usage instructions


***********
1. Ping
***********

Window$: ping <-t> host

*nix:ping <options> host
use "man ping" and "info ping" to see manual for ping command which explains
* its numerous options.

Examples:
Simple ping:
ping  10.252.254.250
PING 10.252.254.250 (10.252.254.250) 56(84) bytes of data.
64 bytes from 10.252.254.250: icmp_seq=1 ttl=60 time=20.0 ms
64 bytes from 10.252.254.250: icmp_seq=2 ttl=60 time=20.0 ms
64 bytes from 10.252.254.250: icmp_seq=3 ttl=60 time=25.6 ms
^C
--- 10.252.254.250 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2437ms
rtt min/avg/max/mdev = 20.049/21.920/25.634/2.628 ms

Reverse Route:
ping -R 10.252.254.250
PING 10.252.254.250 (10.252.254.250) 56(124) bytes of data.
64 bytes from 10.252.254.250: icmp_seq=1 ttl=60 time=45.4 ms
RR: 	41.189.93.108
	41.66.151.213
	10.110.1.89
	10.252.254.250
	10.252.254.250
	10.110.1.86
	10.110.1.90
	41.66.151.209
	41.189.93.97

64 bytes from 10.252.254.250: icmp_seq=2 ttl=60 time=20.9 ms	(same route)
64 bytes from 10.252.254.250: icmp_seq=3 ttl=60 time=21.2 ms	(same route)
64 bytes from 10.252.254.250: icmp_seq=4 ttl=60 time=21.3 ms	(same route)

**************
2. Traceroute
**************

traceroute - print the route packets trace to network host

Window$: tracert host <options>

*nix: traceroute host <options.
use "man traceroute" to see manual

*********************
3. Ipconfig/ifconfig
*********************

Window$: ipconfig /all
Linux: ifconfig /a (Deprecated)
ip a (ip addr), ip link, ip -s (ip -stats)


***************
4. NS check
***************

Window$/*nix: nslookup
*nix: dig

******************
5. SS (Netstat)
******************

ss is utility to investigate sockets.

The netstat command has been replaced with much quicker ss. The command-line
switches are almost the same.
please use "man ss"

Netstat is depreciated, insted use:   
ss
ip route (for netstat-r)
ip -s link (for netstat -i)
ip maddr (for netstat-g)

****************************************************
6. Checking ports availability/reachability 
(firewall blocking ports, apps,etc...)
****************************************************

telnet hostname port
would attempt to connect to any port on any host and give you access to the
raw TCP stream
example test smtp port:

telnet server.domain.net 25
Trying nn.nn.nn.nn...
Connected to server.domain.net.
Escape character is '^]'.
220 relay1.domain.net ESMTP Exim 4.63 Sun, 26 Jul 2015 11:40:46 +0200
ehlo me.here.local  <--------- TYPE THAT FOR EXAMPLE
250-relay1.domain.net Hello me.here.local [clients IP here]
250-SIZE 52428800
250-PIPELINING
250-STARTTLS
250 HELP
quit  <----------------------- Close connection
221 server.domain.net closing connection
Connection closed by foreign host.

from bash shell (Linux)

/dev/tcp/host/port
    If host is a valid hostname or Internet address, and port is an integer
port number
    or service name, bash attempts to open a TCP connection to the
corresponding socket.
/dev/udp/host/port
    If host is a valid hostname or Internet address, and port is an integer
port number
    or service name, bash attempts to open a UDP connection to the
corresponding socket.

USE <Ctrl>+<C> (^C) to quit execution!

example check SSH,Telnet and FTP access
$ cat < /dev/tcp/10.105.111.171/22
SSH-2.0-ROSSSH
^C
$ cat < /dev/tcp/10.105.111.171/23
���� ��#��'^C
$ cat < /dev/tcp/10.105.111.171/21
220 test-board FTP server (MikroTik 6.27) ready
^C

Example test SMTP:
$ cat < /dev/tcp/relay1.domain.net/25
220 relay1.domain.net ESMTP Exim 4.63 Sun, 26 Jul 2015 11:39:50 +0200
^C


****************************
7. Terminal Emulators
****************************
Window$: Terra Term, putty
*nix: as preffered, many available

Tera Term (rarely TeraTerm) is an open-source, free, software implemented,
terminal emulator (communications) program
Terra Term
http://ttssh2.osdn.jp/index.html.en

PuTTY is a free and open-source terminal emulator, serial
console and network file transfer application. It supports several network
protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection. It
can also connect to a serial port (since version 0.59).
PUTTY
http://www.chiark.greenend.org.uk/~sgtatham/putty/


**************************************
8. FTP/Secure Copy - File Transfer
**************************************

Window$: winscp
Linux: mc, scp, ...

WinSCP (Window$ Secure CoPy) is a free and open-source SFTP, FTP, WebDAV and
SCP client for Micro$oft Window$.
WinSCP
http://winscp.net/eng/index.php
WinSCP Documentation
http://winscp.net/eng/docs/start

9. mtr/WinMTR
mtr combines the functionality of the traceroute and  ping programs in a
single network diagnostic tool.

Window$: WinMTR http://winmtr.net/
*nix: mtr
manual can be obtained with "man mtr" and is very useful

example:
mtr -n -t 10.105.116.163

                      My traceroute  [v0.85]
local  (0.0.0.0)          Mon Jul 27 10:23:59 2015
Keys:  Help   Display mode   Restart statistics   Order of fields
 quit                     Packets               Pings
 Host                   Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. 172.28.10.1          0.0%    12    1.9   3.3   1.6  15.8   3.9
 2. 172.31.254.254       0.0%    12    0.2   1.3   0.2  12.8   3.6
 3. 10.255.0.5           0.0%    12    1.5   8.1   1.5  30.7  11.9
 4. 10.255.0.6           0.0%    12   37.0   5.9   1.5  37.0  10.8
 5. 10.105.116.161       0.0%    12    2.9   3.3   2.9   5.3   0.5
 6. 10.105.116.163       0.0%    11   11.5   9.5   8.3  11.5   0.6

***********************
10. Nmap/Zenmap
*************************

To test for open ports on remote host and network
Nmap ("Network Mapper") is a free and open source (license) utility for
network discovery and security auditing.
It is as efficient port scanner.

Window$ and Linux

https://nmap.org/download.html
http://nmap.org/book/man-port-scanning-basics.html

****************************
11. hping
****************************

hping3 - send (almost) arbitrary TCP/IP packets to network hosts

Each attempt to establish a TCP connection to the remote host must be
responded with either by accepting the connection or refusing the connection
by sending a RST package. This information is more than enough to confirm
the presence of the host.

TCP Ping
Window$ .exe  
http://www.elifulkerson.com/projects/tcping.php

linux hping3 ,(tcpping rpmforge)
please see "man hping3" and official website
http://www.hping.org/hping3.html http://wiki.hping.org/

Window$ hping2 http://www.hping.org/download.html

If ICMP has been disabled (security by obscurity) one can use TCP protocol
to check is host alive.

Below two methods are often used to establish online availability of some
host, whenever PING (or ICMP protocol) has been disabled or blocked.
   - Establish TCP connection to, well known publicly available ports like
   - http,ftp,ssh etc.
   - Receive connection refused error with a RST package on initial ACK
   - packet without connection already established.

Examples:

Set SYN tcp flag
hping3 -S -p 80 10.105.100.42
HPING 10.105.100.42 (eth0 10.105.100.42): S set, 40 headers + 0 data bytes
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=SA seq=0 win=14600
rtt=8.5 ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=SA seq=1 win=14600
rtt=7.7 ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=SA seq=2 win=14600
rtt=7.7 ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=SA seq=3 win=14600
rtt=8.4 ms
^C
--- 10.105.100.42 hping statistic ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 7.7/8.1/8.5 ms

Set ACK tcp flag.
hping3 -A -p 80 10.105.100.42
HPING 10.105.100.42 (eth0 10.105.100.42): A set, 40 headers + 0 data bytes
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=R seq=0 win=0 rtt=8.5
ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=R seq=1 win=0 rtt=7.7
ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=R seq=2 win=0 rtt=8.4
ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=R seq=3 win=0 rtt=7.5
ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=R seq=4 win=0 rtt=8.4
ms
^C
--- 10.105.100.42 hping statistic ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 7.5/8.1/8.5 ms


Use HPING as an port scanner:
sudo hping3 --scan <port-range,port-range,...> -S scan-target

Scan router in internal network:
hping3 --scan known -S 10.105.100.42
Scanning 10.105.100.42 (10.105.100.42), port known
340 ports to scan, use -V to see all the replies
+----+-----------+---------+---+-----+-----+-----+
|port| serv name |  flags  |ttl| id  | win | len |
+----+-----------+---------+---+-----+-----+-----+
   21 ftp        : .S..A...  59     0 14600    46
   23 telnet     : .S..A...  59     0 14600    46
   22 ssh        : .S..A...  59     0 14600    46
   80 http       : .S..A...  59     0 14600    46
 2000 cisco-sccp : .S..A...  59     0 14600    46
All replies received. Done.
Not responding ports:

Scan router to establish are all services OK:
hping3 --scan known -S 41.84.20.98
Scanning 41.84.20.98 (41.84.20.98), port known
340 ports to scan, use -V to see all the replies
+----+-----------+---------+---+-----+-----+-----+
|port| serv name |  flags  |ttl| id  | win | len |
+----+-----------+---------+---+-----+-----+-----+
   22 ssh        : .S..A...  56     0  5840    46
   25 smtp       : .S..A...  56     0  5840    46
   53 domain     : .S..A...  56     0  5840    46
   80 http       : .S..A...  55     0 14600    46
  110 pop3       : .S..A...  56     0  5840    46
  443 https      : .S..A...  55     0  5840    46
10000 webmin     : .S..A...  56     0  5840    46
All replies received. Done.

traceroute without ICMP

hping3 10.105.100.42 -A -p 80 -T -t 1 --tr-stop
HPING 10.105.100.42 (eth0 10.105.100.42): A set, 40 headers + 0 data bytes
hop=1 TTL 0 during transit from ip=172.28.10.1 name=UNKNOWN   
hop=1 hoprtt=4.6 ms
hop=2 TTL 0 during transit from ip=172.31.254.254
name=gp-mr-het-mee-1-ae0-wan-1000.ensync.net
hop=2 hoprtt=3.4 ms
hop=3 TTL 0 during transit from ip=10.255.0.5 name=UNKNOWN   
hop=3 hoprtt=15.9 ms
hop=4 TTL 0 during transit from ip=10.255.0.6 name=UNKNOWN   
hop=4 hoprtt=3.5 ms
hop=5 TTL 0 during transit from ip=10.105.100.41
name=10-105-100-41-29.wireless.africainx.net
hop=5 hoprtt=7.9 ms
len=46 ip=10.105.100.42 ttl=59 DF id=0 sport=80 flags=R seq=5 win=0 rtt=6.8
ms

--- 10.105.100.42 hping statistic ---
6 packets transmitted, 6 packets received, 0% packet loss
round-trip min/avg/max = 3.4/7.0/15.9 m

*** Test max troughput:
sudo hping3 -c 10 -d 16000 -S -w 16384 -p 80 --flood  10.105.124.139

*** DOS (this will probabli kill host having with weak cpu/ all routers in
*** the path will be affected)
sudo hping3 -c 10000 -d 120 -S -w 64 -p 80 --flood --rand-source <Target_IP>

**************************
12. nping
**************************

nping == Network packet generation tool / ping utility

download: http://nmap.org/nping/

Ubuntu - part of nmap package
Windows - part of nmap package
Mac Os X - part of nmap package

From nmap.org :
Nping is an open-source tool for network packet generation, response
analysis and response time measurement. Nping allows users to generate
network packets of a wide range of protocols, letting them tune virtually
any field of the protocol headers. While Nping can be used as a simple ping
utility to detect active hosts, it can also be used as a raw packet
generator for network stack stress tests, ARP poisoning, Denial of Service
attacks, route tracing, and other purposes.

https://nmap.org/book/nping-man.html

Example: generate burst of traffic to 45 hosts in 45 different networks - do
1000 packets to each host - send 10000 pps - use ICMP to generate two way
traffic (echo request/response).

nping -H -N -c 100000 --data-length 1000  --icmp  --rate 10000
10.10.6-51.10

Generate approx 825kbps to single target for 10 sec
sudo nping -H -N -c 1000 --data-length 100  --icmp  --rate 100 <target>

Generate 7.6Mbps untill interrupted to single target
sudo nping -H -N -c 0 --data-length 1000  --icmp  --rate 1000 


sudo nping -c 1 --tcp -p 80,22 41.84.22.92
Starting Nping 0.6.40 ( http://nmap.org/nping ) at 2015-08-31 09:36 SAST
SENT (0.0394s) TCP 172.28.10.10:53526 > 41.84.22.92:22 S ttl=64 id=439
iplen=40  seq=2479869044 win=1480 
SENT (1.0397s) TCP 172.28.10.10:53526 > 41.84.22.92:80 S ttl=64 id=439
iplen=40  seq=2479869044 win=1480 
RCVD (1.0399s) TCP 41.84.22.92:22 > 172.28.10.10:53526 SA ttl=55 id=0
iplen=44  seq=1443042119 win=14600 <mss 1460>
 
Max rtt: 1000.433ms | Min rtt: 1000.433ms | Avg rtt: 1000.433ms
Raw packets sent: 2 (80B) | Rcvd: 1 (46B) | Lost: 1 (50.00%)
Nping done: 1 IP address pinged in 1.06 seconds




On-Line utilities:

1. OLC Labs web Site

Local speedest, looking glass, ip calaculator
http://labs.openlinx.co.za/

2. speedtest.net
It can be reched via link from labs.

3. eMail related lookups

MX Toolbox
MX record, blacklists check , etc..
http://mxtoolbox.com/

Valli
The complete IP check for sending Mailservers
http://multirbl.valli.org/

SORBS
The Spam and Open Relay Blocking System
http://www.sorbs.net/

Replacements for deprecated Linux networking commands (eg. ifconfig)

Deprecated command     Replacement command(s)
arp                    ip n (ip neighbor)
ifconfig               ip a (ip addr), ip link, ip -s (ip -stats)
iptunnel               ip tunnel
iwconfig               iw
nameif                 ip link, ifrename
netstat                ss, ip route (for netstat-r), ip -s link (for netstat -i), ip maddr (for netstat-g)
route                  ip r (ip route)


Hping		--->	http://www.hping.org
Nmap		--->	http://www.insecure.org/nmap
Scanlogd	--->	http://www.openwall.com/scanlogd                        
OpenBSD		--->	http://www.openbsd.org
OpenBSD PF	--->	http://www.benzedrine.cx/pf.html
Ettercap    --->	http://ettercap.sourceforge.net
DSniff      --->	http://monkey.org/~dugsong/dsniff                       
RFC1141     --->	http://www.ietf.org/rfc/rfc1141.txt