Locating MAC & IP on Linux

Knowing how to pull network information from the terminal is a fundamental Linux skill. Whether you are troubleshooting a connectivity issue, setting up a server, or just curious about your machine’s network identity — this guide covers every command you need, explained clearly so you understand what each one is actually showing you.

The Network Interfaces on Your Machine

Before looking for specific values, it helps to see all your network interfaces at once:

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ip link show

Sample output:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 ...
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 ...
    link/ether a4:c3:f0:52:1b:3e brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 ...
    link/ether b8:27:eb:7d:44:9a brd ff:ff:ff:ff:ff:ff

Common interface names you will encounter:

Finding Your IP Address

Method 1 — ip (recommended, modern)

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ip addr show

To see a specific interface only:

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ip addr show eth0
ip addr show wlan0

Reading the output:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500
    inet 192.168.1.105/24 brd 192.168.1.255 scope global dynamic eth0
    inet6 fe80::a6c3:f0ff:fe52:1b3e/64 scope link

• inet — your IPv4 address (192.168.1.105) and subnet mask (/24)
• inet6 — your IPv6 address
• scope global — this address is reachable from the network
• scope link — only reachable on the local link (not routable)

Compact one-liner — IPv4 only

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ip -4 addr show | grep inet

Method 2 — hostname

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hostname -I

Prints all IP addresses assigned to the machine, space-separated. Quick and clean.

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# Show just the first IP
hostname -I | awk '{print $1}'

Method 3 — ifconfig (older systems)

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ifconfig

If ifconfig is not installed:

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sudo apt install net-tools      # Debian / Ubuntu
sudo dnf install net-tools      # Fedora / RHEL

Finding Your Hostname

The hostname is your machine’s name on the local network.

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# Short hostname
hostname

# Fully Qualified Domain Name (FQDN)
hostname -f

# Show hostname set in the OS
hostnamectl

hostnamectl is the richest option — it shows the static hostname, icon name, chassis type, kernel version, and OS:

   Static hostname: myserver
         Icon name: computer-desktop
           Chassis: desktop
        Machine ID: a1b2c3d4e5f6...
           Boot ID: ...
  Operating System: Ubuntu 22.04.3 LTS
            Kernel: Linux 6.2.0-36-generic
      Architecture: x86-64

To change the hostname:

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sudo hostnamectl set-hostname new-hostname

Finding Your MAC Address

A MAC (Media Access Control) address is a unique hardware identifier assigned to each network interface card. It is a 12-character hexadecimal value, usually written in pairs: a4:c3:f0:52:1b:3e.

Method 1 — ip link

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ip link show

The MAC address appears on the link/ether line of each interface:

2: eth0: ...
    link/ether a4:c3:f0:52:1b:3e brd ff:ff:ff:ff:ff:ff

One-liner — MAC for a specific interface

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ip link show eth0 | awk '/link\/ether/ {print $2}'

Method 2 — Read directly from /sys

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cat /sys/class/net/eth0/address

Replace eth0 with your interface name. This works on any Linux system regardless of which tools are installed.

Method 3 — ifconfig

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ifconfig eth0 | grep ether

Finding Your Default Gateway

The gateway is the router your machine sends traffic through to reach the internet.

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ip route show

Look for the line starting with default:

default via 192.168.1.1 dev eth0 proto dhcp src 192.168.1.105 metric 100

Here 192.168.1.1 is your default gateway (your router’s IP).

One-liner — print only the gateway

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ip route show default | awk '{print $3}'

Finding Your DNS Servers

DNS servers are used to resolve domain names (like google.com) into IP addresses.

On systems using systemd-resolved (Ubuntu 18.04+)

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resolvectl status

Or for a cleaner summary:

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resolvectl dns

Check /etc/resolv.conf

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cat /etc/resolv.conf

Look for nameserver entries:

nameserver 127.0.0.53
nameserver 8.8.8.8
nameserver 1.1.1.1

Using nmcli (NetworkManager systems)

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nmcli dev show | grep DNS

Full Network Summary with nmcli

If your system uses NetworkManager (most desktop distros do), nmcli gives a rich summary:

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nmcli device show

This shows interface name, MAC address, IP address, gateway, DNS, and connection state all in one output.

For a condensed connection list:

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nmcli connection show

Wi-Fi Specific Information

If you are on a wireless connection, these commands reveal the SSID, signal strength, channel, frequency, and link speed.

Check your Wi-Fi connection details

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iw dev wlan0 link

Sample output:

Connected to b8:27:eb:12:34:56 (on wlan0)
        SSID: MyHomeNetwork
        freq: 5500
        RX: 4523049 bytes (18211 packets)
        TX: 1031222 bytes (7021 packets)
        signal: -52 dBm
        rx bitrate: 300.0 MBit/s MCS 15 40MHz short GI
        tx bitrate: 300.0 MBit/s MCS 15 40MHz short GI

• SSID — the network name you are connected to
• signal — signal strength in dBm (closer to 0 is stronger; -50 is excellent, -80 is poor)
• freq — channel frequency in MHz (2412–2484 = 2.4 GHz, 5160–5825 = 5 GHz)

List all available nearby Wi-Fi networks

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sudo iw dev wlan0 scan | grep -E "SSID:|signal:|freq:"

Using iwconfig (older tool)

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iwconfig wlan0

If not installed:

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sudo apt install wireless-tools

Using nmcli for Wi-Fi

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# Show the currently connected Wi-Fi network
nmcli -f IN-USE,SSID,SIGNAL,BARS,SECURITY device wifi list

# Show detailed info about current connection
nmcli connection show --active

The ARP / Neighbour Table

The ARP (Address Resolution Protocol) table maps IP addresses to MAC addresses for devices on your local network. This is how your machine knows which MAC address belongs to which IP on the same subnet.

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ip neigh show

Sample output:

192.168.1.1   dev eth0 lladdr a8:9c:ed:44:11:22 REACHABLE
192.168.1.102 dev eth0 lladdr dc:a6:32:7b:55:88 STALE
192.168.1.103 dev eth0 lladdr 00:11:32:5a:bc:ef DELAY

ARP states explained

Legacy arp command

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arp -n

Finding Your Public (External) IP Address

Your local IP (192.168.x.x) is only visible inside your home or office network. To find the public IP your traffic exits through, query an external service:

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curl ifconfig.me

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curl icanhazip.com

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curl -s https://ipinfo.io/ip

All three print your public IP address. The -s flag on curl suppresses the progress bar.

For a richer response including location and ISP:

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curl -s https://ipinfo.io

Checking Network Interface Statistics

See bytes sent, received, and error counts for all interfaces:

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ip -s link

Or watch live traffic in real time:

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# Install if needed
sudo apt install nload

# Watch traffic on eth0
nload eth0

Check detailed per-interface counters directly from the kernel:

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cat /proc/net/dev

Checking Open Ports and Active Connections

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# Show all listening ports (TCP and UDP)
ss -tulnp

# Show established connections
ss -tnp

# Legacy alternative
netstat -tulnp

Column guide for ss -tulnp:

Testing Connectivity

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# Basic ping — test if a host is reachable
ping -c 4 google.com

# Trace the route packets take to a destination
traceroute google.com

# Or using the newer combined tool (real-time)
mtr google.com

# Test DNS resolution
nslookup google.com
dig google.com

# Check if a specific port is open on a remote host
nc -zv google.com 443

Quick Reference Cheat Sheet

A Note on Interface Naming

Older Linux systems used simple names like eth0, eth1, wlan0. Modern systems use Predictable Network Interface Names based on hardware location — for example enp3s0 (Ethernet, PCI bus 3, slot 0) or wlp2s0 (Wi-Fi, PCI bus 2, slot 0). The commands in this guide work the same regardless of naming scheme — just substitute your actual interface name, which you can always find with ip link show.