What is Computer Networking¶
Computer Networking is the practice of connecting computers together to enable communication and data exchange between them. In general, Computer Network is a collection of two or more computers. It helps users to communicate more easily. In this article, we are going to discuss the basics which everyone must know before going deep into Computer Networking.
Basic Networking Commands¶
Help Command
/? - Displays help at the command prompt.
/help - Displays help at the command prompt.
command ?
command /
ipconfig /
ipconfig ?
ipconfig¶
ipconfig is undoubtedly one of the fundamental network commands used by data engineers and IT admins and has remained one of the most efficient ways of troubleshooting network connectivity problems in Windows
https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/windows-commands
PS C:\Users\Administrateur> ipconfig /?
USAGE:
ipconfig [/allcompartments] [/? | /all |
/renew [adapter] | /release [adapter] |
/renew6 [adapter] | /release6 [adapter] |
/flushdns | /displaydns | /registerdns |
/showclassid adapter |
/setclassid adapter [classid] |
/showclassid6 adapter |
/setclassid6 adapter [classid] ]
where
adapter Connection name
(wildcard characters * and ? allowed, see examples)
Options:
/? Display this help message
/all Display full configuration information.
/release Release the IPv4 address for the specified adapter.
/release6 Release the IPv6 address for the specified adapter.
/renew Renew the IPv4 address for the specified adapter.
/renew6 Renew the IPv6 address for the specified adapter.
/flushdns Purges the DNS Resolver cache.
/registerdns Refreshes all DHCP leases and re-registers DNS names
/displaydns Display the contents of the DNS Resolver Cache.
/showclassid Displays all the dhcp class IDs allowed for adapter.
/setclassid Modifies the dhcp class id.
/showclassid6 Displays all the IPv6 DHCP class IDs allowed for adapter.
/setclassid6 Modifies the IPv6 DHCP class id.
The default is to display only the IP address, subnet mask and
default gateway for each adapter bound to TCP/IP.
For Release and Renew, if no adapter name is specified, then the IP address
leases for all adapters bound to TCP/IP will be released or renewed.
For Setclassid and Setclassid6, if no ClassId is specified, then the ClassId is removed.
Examples:
> ipconfig ... Show information
> ipconfig /all ... Show detailed information
> ipconfig /renew ... renew all adapters
> ipconfig /renew EL* ... renew any connection that has its
name starting with EL
> ipconfig /release *Con* ... release all matching connections,
eg. "Wired Ethernet Connection 1" or
"Wired Ethernet Connection 2"
> ipconfig /allcompartments ... Show information about all
compartments
> ipconfig /allcompartments /all ... Show detailed information about all
compartments
nslookup¶
PS C:\Users\Administrateur> nslookup /?
Usage:
nslookup [-opt ...] # interactive mode using default server
nslookup [-opt ...] - server # interactive mode using 'server'
nslookup [-opt ...] host # just look up 'host' using default server
nslookup [-opt ...] host server # just look up 'host' using 'server'
PS C:\Users\Administrateur>
hostname¶
Powershell (Windows)
hostname
ping¶
PS C:\Users\Administrateur> ping /?
Usage: ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS]
[-r count] [-s count] [[-j host-list] | [-k host-list]]
[-w timeout] [-R] [-S srcaddr] [-c compartment] [-p]
[-4] [-6] target_name
Options:
-t Ping the specified host until stopped.
To see statistics and continue - type Control-Break;
To stop - type Control-C.
-a Resolve addresses to hostnames.
-n count Number of echo requests to send.
-l size Send buffer size.
-f Set Don't Fragment flag in packet (IPv4-only).
-i TTL Time To Live.
-v TOS Type Of Service (IPv4-only. This setting has been deprecated
and has no effect on the type of service field in the IP
Header).
-r count Record route for count hops (IPv4-only).
-s count Timestamp for count hops (IPv4-only).
-j host-list Loose source route along host-list (IPv4-only).
-k host-list Strict source route along host-list (IPv4-only).
-w timeout Timeout in milliseconds to wait for each reply.
-R Use routing header to test reverse route also (IPv6-only).
Per RFC 5095 the use of this routing header has been
deprecated. Some systems may drop echo requests if
this header is used.
-S srcaddr Source address to use.
-c compartment Routing compartment identifier.
-p Ping a Hyper-V Network Virtualization provider address.
-4 Force using IPv4.
-6 Force using IPv6.
PS C:\Users\Administrateur>
tracert¶
PS C:\Users\Administrateur> tracert /?
Usage: tracert [-d] [-h maximum_hops] [-j host-list] [-w timeout]
[-R] [-S srcaddr] [-4] [-6] target_name
Options:
-d Do not resolve addresses to hostnames.
-h maximum_hops Maximum number of hops to search for target.
-j host-list Loose source route along host-list (IPv4-only).
-w timeout Wait timeout milliseconds for each reply.
-R Trace round-trip path (IPv6-only).
-S srcaddr Source address to use (IPv6-only).
-4 Force using IPv4.
-6 Force using IPv6.
PS C:\Users\Administrateur>
netstat¶
PS C:\Users\Administrateur> netstat /?
Displays protocol statistics and current TCP/IP network connections.
NETSTAT [-a] [-b] [-e] [-f] [-i] [-n] [-o] [-p proto] [-r] [-s] [-t] [-x] [-y] [interval]
-a Displays all connections and listening ports.
-b Displays the executable involved in creating each connection or
listening port. In some cases well-known executables host
multiple independent components, and in these cases the
sequence of components involved in creating the connection
or listening port is displayed. In this case the executable
name is in [] at the bottom, on top is the component it called,
and so forth until TCP/IP was reached. Note that this option
can be time-consuming and will fail unless you have sufficient
permissions.
-e Displays Ethernet statistics. This may be combined with the -s
option.
-f Displays Fully Qualified Domain Names (FQDN) for foreign
addresses.
-i Displays the time spent by a TCP connection in its current state.
-n Displays addresses and port numbers in numerical form.
-o Displays the owning process ID associated with each connection.
-p proto Shows connections for the protocol specified by proto; proto
may be any of: TCP, UDP, TCPv6, or UDPv6. If used with the -s
option to display per-protocol statistics, proto may be any of:
IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, or UDPv6.
-q Displays all connections, listening ports, and bound
nonlistening TCP ports. Bound nonlistening ports may or may not
be associated with an active connection.
-r Displays the routing table.
-s Displays per-protocol statistics. By default, statistics are
shown for IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, and UDPv6;
the -p option may be used to specify a subset of the default.
-t Displays the current connection offload state.
-x Displays NetworkDirect connections, listeners, and shared
endpoints.
-y Displays the TCP connection template for all connections.
Cannot be combined with the other options.
interval Redisplays selected statistics, pausing interval seconds
between each display. Press CTRL+C to stop redisplaying
statistics. If omitted, netstat will print the current
configuration information once.
PS C:\Users\Administrateur>
arp¶
PS C:\Users\Administrateur> arp /?
Displays and modifies the IP-to-Physical address translation tables used by
address resolution protocol (ARP).
ARP -s inet_addr eth_addr [if_addr]
ARP -d inet_addr [if_addr]
ARP -a [inet_addr] [-N if_addr] [-v]
-a Displays current ARP entries by interrogating the current
protocol data. If inet_addr is specified, the IP and Physical
addresses for only the specified computer are displayed. If
more than one network interface uses ARP, entries for each ARP
table are displayed.
-g Same as -a.
-v Displays current ARP entries in verbose mode. All invalid
entries and entries on the loop-back interface will be shown.
inet_addr Specifies an internet address.
-N if_addr Displays the ARP entries for the network interface specified
by if_addr.
-d Deletes the host specified by inet_addr. inet_addr may be
wildcarded with * to delete all hosts.
-s Adds the host and associates the Internet address inet_addr
with the Physical address eth_addr. The Physical address is
given as 6 hexadecimal bytes separated by hyphens. The entry
is permanent.
eth_addr Specifies a physical address.
if_addr If present, this specifies the Internet address of the
interface whose address translation table should be modified.
If not present, the first applicable interface will be used.
Example:
> arp -s 157.55.85.212 00-aa-00-62-c6-09 .... Adds a static entry.
> arp -a .... Displays the arp table.
PS C:\Users\Administrateur>
systeminfo¶
PS C:\Users\Administrateur> systeminfo /?
SYSTEMINFO [/S system [/U username [/P [password]]]] [/FO format] [/NH]
Description:
This tool displays operating system configuration information for
a local or remote machine, including service pack levels.
Parameter List:
/S system Specifies the remote system to connect to.
/U [domain\]user Specifies the user context under which
the command should execute.
/P [password] Specifies the password for the given
user context. Prompts for input if omitted.
/FO format Specifies the format in which the output
is to be displayed.
Valid values: "TABLE", "LIST", "CSV".
/NH Specifies that the "Column Header" should
not be displayed in the output.
Valid only for "TABLE" and "CSV" formats.
/? Displays this help message.
Examples:
SYSTEMINFO
SYSTEMINFO /?
SYSTEMINFO /S system
SYSTEMINFO /S system /U user
SYSTEMINFO /S system /U domain\user /P password /FO TABLE
SYSTEMINFO /S system /FO LIST
SYSTEMINFO /S system /FO CSV /NH
PS C:\Users\Administrateur>
pathping¶
PS C:\Users\Administrateur> pathping /?
Usage: pathping [-g host-list] [-h maximum_hops] [-i address] [-n]
[-p period] [-q num_queries] [-w timeout]
[-4] [-6] target_name
Options:
-g host-list Loose source route along host-list.
-h maximum_hops Maximum number of hops to search for target.
-i address Use the specified source address.
-n Do not resolve addresses to hostnames.
-p period Wait period milliseconds between pings.
-q num_queries Number of queries per hop.
-w timeout Wait timeout milliseconds for each reply.
-4 Force using IPv4.
-6 Force using IPv6.
PS C:\Users\Administrateur>
getmac¶
PS C:\Users\Administrateur> getmac /?
GETMAC [/S system [/U username [/P [password]]]] [/FO format] [/NH] [/V]
Description:
This tool enables an administrator to display the MAC address
for network adapters on a system.
Parameter List:
/S system Specifies the remote system to connect to.
/U [domain\]user Specifies the user context under
which the command should execute.
/P [password] Specifies the password for the given
user context. Prompts for input if omitted.
/FO format Specifies the format in which the output
is to be displayed.
Valid values: "TABLE", "LIST", "CSV".
/NH Specifies that the "Column Header" should
not be displayed in the output.
Valid only for TABLE and CSV formats.
/V Specifies that verbose output is displayed.
/? Displays this help message.
Examples:
GETMAC /?
GETMAC /FO csv
GETMAC /S system /NH /V
GETMAC /S system /U user
GETMAC /S system /U domain\user /P password /FO list /V
GETMAC /S system /U domain\user /P password /FO table /NH
PS C:\Users\Administrateur>