Commonly used network management tools
What are the commonly used network management tools and describe how to use them in the form of examples.
Ifconfig command
# ifconfig-a
# ifconfig INTERFACE [up | down]
Ifconfiginterface [aftype] options | address...
# ifconfig INTERFACE IP/mask [up]
# ifconfig INTERFACE IP netmask MASK
Route command
View: route-n
Add: route add
Routeadd [- net |-host] target [netmask Nm] [gw Gw] [[dev] If]
Add:
Route add [- net |-host] target [netmask Nm] [gw GW] [[dev] If]
Example: route add-net 10.0.0.0 gw 8 gw 192.168.10.1 dev eth2
Route add-net 0.0.0.0amp 0.0.0.0 gw192.168.10.1
Route add default gw 192.168.10.1
Delete:
Route del [- net |-host] target [gw Gw] [netmask Nm] [[dev] If]
Example: route del-net 10.0.0.0 gw 8 gw 192.168.10.1
Route del default
Netstat command
Printnetwork connections, routing tables, interface statistics, masqueradeconnections, and multicast memberships
Show routing table: netstat-rn
-r: displays the kernel routing table
-n: numeric format
Show network connections:
Netstat [--tcp |-t] [--udp |-- udplite |-U] [--sctp |-S] [--raw |-w] [--listening |-l] [--all |-a] [--numeric |-n] [--extend |-e [--extend |-e] [--program |-p]
-t:TCP protocol related connections, all connections have their own status; FSM (Finate State Machine)
-u:UDP related connections
-w:raw socket related connections
-l: a connection in the listening state
-a: all statu
-n: display IP and Port in digital format
-e: extended format
-p: displays related processes and PID
Common combinations:
-tan,-uan,-tnl,-unl,-tunlp
Transport layer protocols:
Tcp: a connection-oriented protocol; establish a virtual link before the communication starts, and dismantle the connection after the communication is completed
Udp: connectionless protocol; sending data messages directly
Displays the statistics of the interface:
Netstat {- interfaces |-I |-I} [iface] [--all |-a] [--extend |-e] [--verbose |-v] [--program |-p] [--numeric |-n]
All interfaces:
Netstat-I
Specify the interface:
Netstat-I
Ip command
Show/ manipulate routing, devices, policy routing and tunnels
Ip [OPTIONS] OBJECT {COMMAND | help}
OBJECT:= {link | addr | route | netns}
Note: OBJECT can be abbreviated, and so can the subcommands of each OBJECT.
Ip OBJECT:
Iplink: network device configuration
Ip link set-change device attributes
DevNAME (default): indicates the device to be managed. The dev keyword can be omitted.
Up and down:
Multicaston or multicast off: enable or disable multicast featur
NameNAME: rename interfac
MtuNUMBER: sets the size of MTU. Default is 1500.
NetnsPID:ns is namespace and is used to move the interface to the specified network namespace
Ip link show-display device attributes
Ip link help-displays brief usage help
Ip netns:-manage network namespaces.
Ip netns list: list all netns
Ip netns add NAME: creates the specified netns
Ip netns del NAME: deletes the specified netns
Ip netns exec NAME COMMAND: runs the command in the specified netns
Ipaddress-protocol address management.
Ipaddress add-add new protocol address
Ip addr add IFADDR dev IFACE
[labelNAME]: indicates the interface alias for the additional address
[broadcastADDRESS]: broadcast address; will be calculated automatically based on IP and NETMASK
[scopeSCOPE_VALUE]:
Global: globally available
Link: API is available
Host: only available locally
Ipaddress delete-delete protocol address
Ipaddr delete IFADDR dev IFACE
Ipaddress show-look at protocol addresses
Ip addr list [IFACE]: displays the address of the interface
Ipaddress flush-flush protocol addresses
Ip addr flush dev IFACE
Ip route command
Iproute-routing table management
Iproute add-add new route
Iproute change-change route
Iproute replace-change or add new one
Ip route add TYPE PREFIX via GW [dev IFACE] [src SOURCE_IP]
Example:
# ip route add 192.168.0.0/24 via10.0.0.1 dev eth2 src 10.0.20.100
# ip route add default via GW
Iproute delete-delete route
Ip route del TYPE PRIFIX
Example:
# ip route delete 192.168.1.0/24
Iproute show-list routes
TYPEPRIFIX
Iproute flush-flush routing tables
TYPE PRIFIX
Iproute get-get a single route
Ip route get TYPE PRIFIX
Example: iproute get 192.168.0.0Comp24
Ss command:
Ss [options] [FILTER]
Options:
-related connections of t:TCP protocol
-u:UDP related connections
-w:raw socket related connections
-l: connection for listening statu
-a: connections for all statu
-n: numeric format
-p: related programs and their PID
-e: extended format information
-m: memory usage
-o: timer information
FILTER:= [state TCP-STATE] [EXPRESSION]
Common status of TCP:
TCPFSM:
LISTEN: monitoring
ESTABLISEHD: established connection
FIN_WAIT_1:
FIN_WAIT_2:
SYN_SENT:
SYN_RECV:
CLOSED:
EXPRESSION:
Dport=
Sport=
Example:'(dport =: 22 or sport =: 22)'
~] # ss-tan'(dport =: 22 or sport =: 22)'
~] # ss-tan state ESTABLISHED
