ibook

[!DANGER] @DEPRECATED

reference:

interface

change interface name

Permanent Solution

$ sudo touch /etc/udev/rules.d/10-network.rules
$ sudo bash -c "cat > /etc/udev/rules.d/10-network.rules" << EOF
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="<INTERFACE_MAC_ADDRESS>", KERNEL=="<ORIGINAL_INTERFACE_NAME>", NAME="<NEW_INTERFACE_NAME>"
EOF

temporary Solution

$ sudo ifconfig <ORIGINAL_INTERFACE_NAME> down
$ sudo ip link set <ORIGINAL_INTERFACE_NAME> name <NEW_INTERFACE_NAME>
$ sudo ifconfig <NEW_INTERFACE_NAME>

show

ethtool

$ sudo ethtool eth0
Settings for eth0:
    Supported ports: [ TP ]
    Supported link modes:   10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Supported pause frame use: No
    Supports auto-negotiation: Yes
    Supported FEC modes: Not reported
    Advertised link modes:  10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Advertised pause frame use: No
    Advertised auto-negotiation: Yes
    Advertised FEC modes: Not reported
    Speed: 100Mb/s
    Duplex: Full
    Port: Twisted Pair
    PHYAD: 1
    Transceiver: internal
    Auto-negotiation: on
    MDI-X: on (auto)
    Supports Wake-on: pumbg
    Wake-on: g
    Current message level: 0x00000007 (7)
                   drv probe link
    Link detected: yes

list hardware

$ sudo lshw -class network
  *-network
       description: Wireless interface
       product: Wireless 8260
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: wlan0
       version: 3a
       serial: 34:f3:9a:52:75:65
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=4.15.0-23-generic firmware=34.0.1 ip=192.168.10.235 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: irq:129 memory:e4100000-e4101fff
  *-network
       description: Ethernet interface
       product: Ethernet Connection (2) I219-LM
       vendor: Intel Corporation
       physical id: 1f.6
       bus info: pci@0000:00:1f.6
       logical name: eth0
       version: 31
       serial: 30:e1:71:95:19:bc
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k duplex=full firmware=0.8-4 ip=130.147.182.57 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s
       resources: irq:127 memory:e4300000-e431ffff
  *-network:0
       description: Ethernet interface
       physical id: 2
       logical name: veth680e7b1b
       serial: 86:86:ae:b1:3f:c3
       size: 10Gbit/s
       capabilities: ethernet physical
       configuration: autonegotiation=off broadcast=yes driver=veth driverversion=1.0 duplex=full link=yes multicast=yes port=twisted pair speed=10Gbit/s
  *-network:1
       description: Ethernet interface
       physical id: 3
       logical name: vethdd057c06
       serial: ae:b1:42:e3:30:d0
       size: 10Gbit/s
       capabilities: ethernet physical
       configuration: autonegotiation=off broadcast=yes driver=veth driverversion=1.0 duplex=full link=yes multicast=yes port=twisted pair speed=10Gbit/s
  *-network:2
       description: Ethernet interface
       physical id: 4
       logical name: vethfe693595
       serial: 16:ec:cd:4e:c3:d8
       size: 10Gbit/s
       capabilities: ethernet physical
       configuration: autonegotiation=off broadcast=yes driver=veth driverversion=1.0 duplex=full link=yes multicast=yes port=twisted pair speed=10Gbit/s
  *-network:3
       description: Ethernet interface
       physical id: 5
       logical name: flannel.1
       serial: 2a:2b:77:a7:35:8f
       capabilities: ethernet physical
       configuration: broadcast=yes driver=vxlan driverversion=0.1 ip=10.244.0.0 link=yes multicast=yes
  *-network:4
       description: Ethernet interface
       physical id: 6
       logical name: cni0
       serial: 0a:58:0a:f4:00:01
       capabilities: ethernet physical
       configuration: broadcast=yes driver=bridge driverversion=2.3 firmware=N/A ip=10.244.0.1 link=yes multicast=yes
  *-network:5
       description: Ethernet interface
       physical id: 7
       logical name: docker0
       serial: 02:42:99:41:e5:02
       capabilities: ethernet physical
       configuration: broadcast=yes driver=bridge driverversion=2.3 firmware=N/A ip=172.17.0.1 link=no multicast=yes
  *-network:6
       description: Ethernet interface
       physical id: 8
       logical name: vethc1b38134
       serial: 76:6a:6c:0f:e8:a1
       size: 10Gbit/s
       capabilities: ethernet physical
       configuration: autonegotiation=off broadcast=yes driver=veth driverversion=1.0 duplex=full link=yes multicast=yes port=twisted pair speed=10Gbit/s

route

$ nslookup gitlab.domain.com
Server:     130.147.236.5
Address:    130.147.236.5#53

Non-authoritative answer:
Name:   pww.gitlab.cdi.mycompany.com
Address: 130.147.219.15

$ ip route get 130.147.219.15
130.147.219.15 dev eno1 src 130.147.182.240 uid 1000
    cache

$ nslookup github.com
Server:     130.147.236.5
Address:    130.147.236.5#53

Non-authoritative answer:
Name:   github.com
Address: 192.30.253.112
Name:   github.com
Address: 192.30.253.113

$ ip route get 192.30.253.113
192.30.253.113 via 192.168.10.1 dev wlan0 src 192.168.11.166 uid 1000
    cache

DNS

add new DNS permanently

$ sudo apt install resolvconf
$ sudo cp /etc/resolvconf/resolv.conf.d/head{,.org}
$ sudo bash -c "cat > /etc/resolvconf/resolv.conf.d/head" << EOF
nameserver 130.147.236.5
nameserver 161.92.35.78
search cn-132.lan.mycompany.com
EOF

$ sudo resolvconf -u

$ cat /etc/resolv.conf
nameserver 127.0.0.53

$ sudo resolvconf -u

$ cat /etc/resolv.conf
nameserver 130.147.236.5
nameserver 161.92.35.78
nameserver 127.0.0.53
search cn-132.lan.mycompany.com

port redirection

$ sudo iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

$ sudo iptables -I INPUT 1 -p tcp --dport 8080 -j ACCEPT
$ sudo iptables -I INPUT 1 -p tcp --dport 80 -j ACCEPT
$ sudo iptables -A PREROUTING -t nat -i ens32 -p tcp --dport 80 -j REDIRECT --to-port 8080
$ sudo iptables -t nat -I OUTPUT -p tcp -d 127.0.0.1 --dport 80 -j REDIRECT --to-ports 8080
$ sudo iptables -t nat -I OUTPUT -p tcp -o lo --dport 80 -j REDIRECT --to-ports 8080

$ sudo iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:80
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:8080
Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

$ sudo netfilter-persistent save
run-parts: executing /usr/share/netfilter-persistent/plugins.d/15-ip4tables save
run-parts: executing /usr/share/netfilter-persistent/plugins.d/25-ip6tables save
$ sudo iptables-save > /etc/iptables/rules.v4

proxy setup

network speed

$ ifstat -n -i en7
       en7
 KB/s in  KB/s out
    7.35      1.15
    4.91      1.02
    6.05      0.80
    8.36      1.78

wifi

iwconfig

nmcli

nmcli-1

nmcli-2

nmtui

nmtui-1 nmtui-2

netmask

[!NOTE|label:references:]

conversion

[!NOTE|label:references:]

# bin -> dec
$ bc <<< 'ibase=2;11111111;11111111;11000000;00000000' | paste -sd. -
255.255.192.0

# bin -> hex
$ bc <<< 'obase=16;ibase=2;11111111;11111111;11000000;00000000' | awk '{ printf "%04s\n", $1 }' | paste -sd. -
00FF.00FF.00C0.0000

# dec -> bin
$ bc <<< 'ibase=10;obase=2;255;255;240;0' | numfmt --format %08f | paste -sd' ' -
11111111 11111111 11110000 00000000

# dec -> hex
$ bc <<< 'ibase=10;obase=16;255;255;240;0' | awk '{ printf "%04s\n", $1 }' | paste -sd. -
00FF.00FF.00F0.0000

# hex -> bin
$ bc <<< 'ibase=16;obase=2;FF;FF;EE;0A' | numfmt --format %08f | paste -sd' ' -
11111111 11111111 11101110 00001010

# hex -> dec
$ bc <<< 'ibase=16;FF;FF;EE;0A' | paste -sd. -
255.255.238.10

basic concept

[!TIP|label:what is netmask] A netmask is a 32-bit binary mask used to divide an IP address into subnets and specify the network’s available hosts.

==>

example

if netmask using n-bit, then supported hosts/nets = 2^(32-<n>) - 1 - 1. i.e.:

if netmask using 255.255.x.x

  1. convert netmask decimal to binary, and get bit and then get wildcard. i.e.:
    • netmask : 255.255.255.192
    • decimal to binary :

    [!TIP]

    $ bc -l <<< 'obase=2;255;255;192;0' | awk '{ printf "%08d\n", $0 }' | xargs
11111111 11111111 11000000 00000000
$ bc -l <<< 'obase=2;255;255;192;0' | numfmt --format=%08f | xargs
11111111 11111111 11000000 00000000

    192
    = 128 + 64
    = 2^7 + 2^6
    = 

    10000000 + 01000000
         - netmask :

      255   .  255   .  255   .  192    
    11111111 11111111 11111111 11000000
    |---------------------------|
                 26-bit

    = 1x3x8 + 1x2 + 0x6 = 26 - wildcard :

       0    .   0    .   0    .   63   
    00000000 00000000 00000000 00111111
                                 |----|
                                  6-bit

    = 0x3x8 + 0x2 + 1x6 = 6 === 32 - 26 = 6 - IPs : 2^6 - 1 - 1 = 64 - 2 = 62 = 10.0.0.1 ~ 10.0.0.62 - boardcast : 10.0.0.63

  2. 255.255.255.255 - <netmask>, and then convert decimal to binary
    • netmask : 255.255.240.0
    • wildcard :

    [!TIP]

    $ bc -l <<< 'obase=2;0;0;15;255' | awk '{ printf "%08d\n", $0 }' | xargs
00000000 00000000 00001111 11111111
$ bc <<< 'obase=2; 0;0;15;255' | numfmt --format=%08f | xargs
00000000 00000000 00001111 11111111

    255.255.255.255 - 255.255.240.0 = 0.0.15.255 =

        0    .    0   .    15  .  255 
     00000000 00000000 00001111 11111111
                           |-----------|
                               12-bit
         - IPs : `2^12 - 1 - 1` = `4094` =

    10.0.0.1 ~ 10.0.0.15.254 
                      -- 
                  0.0.15.255    # 255.255.255.255 - 255.255.240.0 = 0.0.15.255 
         - boardcast : `10.0.15.255`

netmask quick reference

# BITS # HOSTS NETMASK CLASS
/4 268435456 240.0.0.0 A
/5 134217728 248.0.0.0 A
/6 67108864 252.0.0.0 A
/7 33554432 254.0.0.0 A
/8 16777216 255.0.0.0 A
/9 8388608 255.128.0.0 B
/10 4194304 255.192.0.0 B
/11 2097152 255.224.0.0 B
/12 1048576 255.240.0.0 B
/13 524288 255.248.0.0 B
/14 262144 255.252.0.0 B
/15 131072 255.254.0.0 B
/16 65536 255.255.0.0 B
/17 32768 255.255.128.0 C
/18 16384 255.255.192.0 C
/19 8192 255.255.224.0 C
/20 4096 255.255.240.0 C
/21 2048 255.255.248.0 C
/22 1024 255.255.252.0 C
/23 512 255.255.254.0 C
/24 256 255.255.255.0 C
/25 128 255.255.255.128 -
/26 64 255.255.255.192 -
/27 32 255.255.255.224 -
/28 16 255.255.255.240 -
/29 8 255.255.255.248 -
/30 4 255.255.255.252 -
/31 - - -
/32 1 255.255.255.255 -

ipcalc

[!NOTE|label:references:]